Piedmont Master GardenersArticles – Piedmont Master Gardeners

The Edible Garden in May

Ralph Morini — Fri, 01 May 2026 15:14:59 +0000

After a winter of wild weather, the Virginia Piedmont is finally settling into a steadier spring. Gardeners who capitalized on warming temperatures and planted spring crops early, are likely enjoying fresh produce already. Those who waited for May to arrive can begin planting summer vegetables through May and into June. While climate change has moved our average last frost date in Hardiness Zone 7b, to April 5-15th (from April 15-25th), there is still the possibility of a late frost. Best to keep an eye on the forecast and be prepared to cover any tender plants if a late frost arrives. Even with the risks, most of us will be plowing ahead, so to speak.

Per the VA Cooperative Extension Home Garden Vegetable Planting Guide, May is not a recommended planting time for cool weather crops including asparagus, beets, broccoli, brussels sprouts, kale/collards/spinach and other cool weather greens, lettuce, carrots and turnips. Warm weather plants that are recommended for May include many types of beans, corn, cucumbers, eggplant, melons, pumpkins, summer squash and tomatoes.

Soil thermometer. Photo: Colorado State Extension

Some Specifics

Soil temperature plays a major role in seed germination and transplant health. Cool-weather crops like spinach, lettuce, greens, peas, onions, and root crops need soil temperatures in the 35-40° range. Actually, 80° is the optimum temperature for germination but these crops don’t grow well in the heat after germination, so we compromise. Starting seeds indoors and transplanting, (except root vegetables, which don’t transplant well), or purchasing transplants are the most efficient practices to get plants growing.

Warm-weather crops including tomatoes, corn, and beans need at least 55° soil. Peppers, cucumbers, melons, and sweet potatoes want at least 60° and eggplants need 70° or higher. Planting too early risks seed rotting prior to germination.

You can test soil temperature with a soil thermometer, available at most garden shops. Poke the thermometer about 2 ½ inches into the soil. Since soil temperature will vary throughout the day and night, a good average is found between 10 and 11 am. It’s good to track the incoming weather reports to be sure you are ready to deal with a cold snap if necessary.

New asparagus patch. Photo: R Morini

If you have a mature asparagus patch, you are likely harvesting fresh spears now. If you are installing a new bed, it is too late to plant now in our Hardiness Zone. It is best to start planning for next year. Prep the bed this fall and plant next spring between late March and late April. To be sure you get it right, check out the good advice in Growing Asparagus in A Home Garden from the University of Maryland Extension.

Other tips for May vegetable gardening in our area:

Tomato transplants. Photo: R Morini

Tomato transplants are ready to be placed in the garden when they have 5-7 leaves. When transplanting tomatoes, place two-thirds of the plant below the soil surface. Pull leaves off the bottom two-thirds of the plants and either dig the planting hole deep enough to stand the plant up or lay the bottom half on its side in the hole, and gently bend the stem to set the upper half vertically above the soil surface. Tomatoes will add roots underground and build a stronger root system.

When choosing your tomato varieties, consider determinate types that ripen within a narrow time period if you are a canner and want a single harvest. Indeterminate varieties will provide a steady supply of ripening fruits until frost, if well cared for.

Eggplants like 80° to 90° temperatures and plenty of water. It’s best to water them thoroughly twice a week during dry periods.

Speaking of moisture, beans, peas, and other legumes that fix soil nitrogen produce fewer, smaller root nodules when water-stressed. It is important to keep them well-watered.

Extend your harvest season by planting sweet corn and beans every two weeks through mid-late July. An alternative with corn is to plant early-, mid-, and late-maturing varieties at the same time.

Missing corn kernels on your corn ears? This may be the result of poor pollination. Sweet corn is wind pollinated. Pollen from the corn flower must reach every strand of silk on each growing ear to develop fully kernelled mature corn ears. Block planting in short rows (3-4 rows or more) will pollinate more successfully than 1 or 2 long rows. Find more information in VA Cooperative Extension publication Sweet Corn.

Keep potatoes covered. The skins of potatoes exposed to sunlight will turn green. This green color comes from the pigment chlorophyll, which is produced as a response to sunlight. “Green Potatoes” will often develop a bitter taste and may even become toxic. This can be prevented by covering the exposed potatoes with soil, straw or leaf mulch. It is possible to plant potatoes until mid-May. Find planting and care information at Growing Potatoes in a Home Garden from the University of Maryland Extension.

To control weeds growing alongside crops, destroy them before they develop seeds. Removing them with weeding tools is a good practice but don’t cultivate deeply; this can cause damage to shallow vegetable roots. Mulch and compost can also reduce weed growth, but be sure to avoid adding amendments carrying seeds.

Fertilization is an important element in maximizing garden output. There are problems with over- and under-fertilizing, different impacts from synthetic and natural fertilizers, and soil health issues to consider. If you would benefit from more insight into fertilizer use, check out The Garden Shed article “A Fertilization Primer”

When watermelons, muskmelons, squash, and cucumbers are planted in a hill and spreading along the ground, place a stick upright in the middle of the hill and leave it there. Later in the summer when the hill becomes hidden by the vines, you will know where to water. You’ll save time looking for the main root and save water as well. An alternative is to grow vining plants vertically rather than letting them spread across the garden area. To learn more about vertical gardening check out the Garden Shed article Vertical Gardening with Trellises, Stakes and Cages.

If you have had insect issues with these cucurbit plants in the past, consider delaying planting until as late as mid-july to reduce the risk of infestation.

When transplanting seedlings in peat pots, gently tear off the top inch of the pot; the upper edges of the pot should be covered with soil to avoid wicking water away from the soil surface, reducing the moisture reaching the plant roots.

Cabbage worms on kale. Photo: R Morini

If you are growing Cole crops, including cabbage, broccoli, cauliflower, kale, collards, or other greens, May means the arrival of cabbage worms that can decimate your crop. Options for control include hand-picking, row covers or using an organic pesticide like Bt (Bacillus thuringiensis). I have also had luck hanging decoys of cabbage moths within the crop. The decoys appear to discourage territorial moths from laying their eggs in that location. Please note that decoys are not supported by any Extension research that I can find, but they have support from numerous other gardening organizations.

Baby bluebird awaiting caterpillar delivery. Photo: R Morini

My favorite anti-cabbage moth preventive is adding pollinator plants and bluebird houses. Finding a healthy natural balance really works. Baby bluebirds consume several hundred caterpillars, including cabbage worms, during their two-weeks as nestlings. It makes sense to support them while minimizing pest impact sustainably.

For related information, check out Garden Shed articles “OMG What’s Eating the Broccoli”, “Row Covers: a Gardening Season Extender with Benefits” and Plant a Pollinator Paradise.

To preserve leftover seeds, store them in a sealed container and refrigerate them. Place a desiccant, such as a few layers of paper towels with 2 tablespoons of powdered milk inside the container to absorb moisture.

Triple compost bin at Bread and Roses Ministry. Photo: R Morini

This is a great time to start a fresh batch of compost. The warm temperatures will speed up decomposition if you keep the pile moist and aerated. Grass clippings and kitchen scraps become plentiful as we begin mowing lawns and eating seasonal fruits and vegetables. If you’ve saved some leaves from last fall or chemical free papers and cardboard from home use, you have what you need to create a good compost batch that can be ready for use this fall. VCE publication Making Compost from Yard Waste offers helpful guidance for several composting approaches.

If you are a fruit grower and want to add native fruit plantings to the orchard, consider pawpaws. There is good advice for growing and eating pawpaws in the Garden Shed articles “Pawpaws: Resilient and Delectable Natives” and “Yummy Recipes With Pawpaws”. Go native!

Garden season is in full swing now. Let’s get out there and enjoy it!

Resources:

VA Cooperative Extension: May Tips: Vegetables https://albemarle.ext.vt.edu/content/dam/albemarle_ext_vt_edu/files/hort-tip-sheets/5-14-veg.pdf

“Soil Temperatures by Vegetable,” K-State Extension: https://enewsletters.k-state.edu/postrockdistrictfcs/2021/02/23/soil-temperatures-and-vegetables/

Cover photo: May edible garden. Photo: R Morini

Looks Like a Moth, Acts Like a Vampire: The Spotted Lanternfly (SLF)

Charles D'Aniello — Fri, 01 May 2026 15:25:06 +0000

Looks Like a Moth, Acts Like a Vampire: The Spotted Lanternfly (SLF)

Unpacking the title alone tells you a lot about what a spotted lanternfly is—and what it isn’t. For starters, it only sort of looks like a moth. It doesn’t “suck” blood—thank goodness—it “sucks” sap, which is very bad news if you happen to be a plant. And despite the name, it isn’t a fly at all; it’s a planthopper. For an insect with wings, SLF is a remarkably poor flier, although it’s a strong jumper.

Reunited: Tree and “Fly”

The real story doesn’t begin with the lanternfly at all. It begins with a plant that reached America more than 200 years earlier and—if you didn’t know better—seemed to be waiting for its perfect partner in invasion. The plant arrived on purpose. The lanternfly did not. It slipped into the country the way many invasive insects do: hidden on a load of construction materials, unnoticed until it was far too late. Tree of heaven (TOH or ToH) and the spotted lanternfly evolved in China and overlapping regions of Asia, and scientists now know that feeding on tree of heaven — Ailanthus altissima — makes lanternflies unpalatable to predators that might otherwise eat them. In other words, the tree gives the insect a chemical shield. University of Michigan Extension notes: “Immature SLF nymphs and adults have higher survival rates and adult females produce many more eggs when they feed on ToH compared with other tree species.” The scientific name Ailanthus translates as “tree reaching for the sky” and altissima means tallest, thus tree of heaven.

Mature Ailanthus altissima, 5 September 2025, Wikimedia Commons. Photo: Darkone. CC BY-SA 2.5

As New York City surged into a major growth spurt in the early 19th century, municipal leaders decided the streets needed trees—and they needed them fast. They wanted something that would shoot up straight and tall, tolerate urban congestion, and thrive with minimal fuss. Tree of heaven fit the bill: it can grow 50 feet in 25 years and ultimately reach 60–80 feet. Prince’s Nursery, then the region’s dominant supplier, eagerly promoted it. Its 1823 catalog gave the species star billing, and its exotic origin in China only heightened its appeal to a city hungry for worldly flair.

The tree had already been circulating in the West for decades. It was introduced to Europe in the 1740s during a wave of fascination with Chinese plants, and it reached the Philadelphia area around 1784 thanks to the botanically ambitious William Hamilton. In China, it already had a long cultural and medicinal history. In a neat example of ecological irony, the spotted lanternfly was first detected in the U.S. massing on tree of heaven trunks near a stone yard in Berks County, Pennsylvania, in 2014 and large aggregations on tree of heaven were widely reported in the years that followed. SLF was first detected in Virginia in 2018 and in Albemarle County in July 2021. The two species, reunited on American soil, quickly formed an invasive powerhouse.

As it turned out, tree of heaven could also shrug off the waves of inchworms that plagued mid‑19th‑century American cities. The caterpillars devoured the same diverse street trees beloved by residents, but tree of heaven, researcher Catherine Neur observes, was barely touched. Its one serious drawback was the foul odor produced by male trees, which earned it the nickname “stink tree.” In the age of miasma theory, when foul smells were believed to cause disease, this was more than a nuisance. Congress regulated street tree plantings in Washington, D.C. in the 1850s, and foul‑smelling species were discouraged, revulsion quickly spread to New York City. Some critics even tied their dislike to the tree’s foreign origins.

In the end, its resistance to inchworms saved it. It withstood the worst an urban environment could throw at it, thriving opportunistically in disturbed spaces—from vacant lots to cracked sidewalks. Simply cutting it down, as we’ll see, was never a quick fix. It became a symbol of resilience, a quality immortalized in Betty Smith’s A Tree Grows in Brooklyn (1943), where it stands as a metaphor for the protagonist’s determination to better herself. The tree spread westward as well. It was introduced to California in the 1850s by Chinese immigrants for medicinal and cultural reasons. And in 1861, it was deliberately planted in Philadelphia as a host for Samia cynthia, the Ailanthus silk moth, in hopes of launching an American silk industry that never materialized.

Today, tree of heaven is the preferred host of the spotted lanternfly—lanternflies can survive without it, but life is undeniably better for them with it. If given a choice they choose it over other targets. Beyond that, the tree is a formidable invasive in its own right, forming dense stands that block sunlight and releasing allelopathic chemicals that inhibit or kill surrounding vegetation. And it does not go down without a fight: it resprouts vigorously from cut trunks, and because it is dioecious, females produce vast numbers of seeds while males produce enormous quantities of pollen‑rich flowers. Admired once, if only intermittently, tree of heaven is now internationally reviled.

Look-alikes: Tree and Bug

Evolution often produces organisms that resemble one another, yet each lineage retains subtle traits that set it apart—a principle that shows up clearly in the many look‑alikes associated with both tree of heaven and the spotted lanternfly. Tree of heaven is frequently mistaken for staghorn sumac, black walnut, black locust, and several hickory species. Spotted lanternfly look‑alikes vary by life stage: adults can resemble tiger moths, giant leopard moths, Ailanthus moths, and underwing moths; nymphs are easily confused with wheel bug nymphs, boxelder bugs, milkweed bugs, and brown marmorated stink bug nymphs; and egg masses can be mistaken for spongy moth egg masses, wheel bug egg clusters, or even lichen patches and mud dauber nests. Because the overlap can be confusing, reliable references include Virginia Cooperative Extension’s Possible Spotted Lanternfly Immature Look‑alikes in Virginia, Michigan Invasive Species’ Spotted Lanternfly Look‑Alikes, and Penn State Extension’s Tree of Heaven: Accurate Identification. Two quick field clues help cut through the uncertainty: spotted lanternflies hop vigorously, and tree of heaven flowers give off a distinctive odor often compared to stale peanut butter or cat urine. The notorious tree of heaven odor comes from male flowers. Female trees do not produce the foul bloom smell. Both sexes, however, have smelly leaves and twigs when bruised.

Know the Enemy

The spotted lanternfly (Lycorma delicatula) carries a name rooted in an 18th‑century scientific misunderstanding. Early naturalists, working from preserved specimens and travelers’ accounts, believed that certain lanternflies in the family Fulgoridae were bioluminescent, with their elongated, snout‑like head structures glowing at night. Although that misconception applied to other members of the family—not Lycorma delicatula specifically—the name “lanternfly” persisted. Today we know that none of these insects actually emit light. Nonetheless, the species remains classified within Fulgoridae because its morphology (physical structure) aligns with the family’s traits. This taxonomic history is preserved in its name: Fulgoridae derives from the Latin fulgor, meaning “brightness” or “lightning,” while the species name delicatula means “dainty” or “delicate.” However, the etymological origin of the genus name Lycorma remains historically unclear.

Lycorma delicatula in Brooklyn Botanic Garden, 4 September 2021. Wikimedia Commons. Photo: Rhododendrites. CC BY-SA 4.0

Spotted lanternflies are planthoppers, not flies, and adults are strikingly beautiful—for a reason. At rest, they fold their wings tight against tree bark, using the mottled forewings as camouflage. But when they’re about to jump or feel threatened, they flash those vivid red-and-black hindwings. It’s a warning display, perhaps advertising to predators that they may be unpalatable thanks to toxins picked up from their preferred host, the tree of heaven. Its common North American relatives include cicadas, leafhoppers, treehoppers, and various types of planthoppers, such as the small green acanaloniid or the wax-covered Flatid.

Spotted lanternflies can fly, but they’re not good at it. Most of what looks like flight is really a short glide or a controlled fall. They climb upward first, then launch themselves, and the distance they travel depends largely on how high they were when they jumped. They cannot gain altitude under their own power. Their real strength is jumping. Like other planthoppers, they use a high‑speed hydraulic system in their hind legs to catapult themselves with remarkable force. Once airborne, they can steer slightly by opening their wings, but they rely on their legs—not flight—for most movement. When they land, specialized adhesive pads on their feet allow them to stick easily to bark, leaves, metal, or even glass. From nymphs to adults, they are driven to climb upward. Nymphs make the journey to find the tenderest plant parts, falling only contributes to dispersal on the host plant or other plants.

Lycorma delicatula, Ransolph, NJ, 8 September 2022. Part of an INaturalist observation. Wikimedia Commons. Photo: gwtstl. CC BY 4.0

Spotted lanternflies feed with a needle‑like mouthpart that pierces a plant’s phloem. They don’t actively suck sap; although they possess a pump mechanism, phloem feeders rely primarily on the plant’s own positive vascular pressure to push sap into the insect. Because phloem sap is sugar‑rich but nutrient‑poor, SLF must process huge volumes of it—producing correspondingly large amounts of sugary waste called honeydew. That honeydew is trouble. It creates a perfect substrate for sooty mold, which coats leaves and bark and interferes with photosynthesis. The sugary deposits also attract other insects, especially wasps, turning an infested tree into a sticky, buzzing mess.

Lycorma delicatula life stages and relative sizes, 9 October 2021. Wikimedia Commons. Photo: Published by Oxford University Press, image by US government employee. Public Domain

The reproductive cycle of the spotted lanternfly begins in late summer. Adults reach sexual maturity in late August or September, and females are slightly larger and more robust than males, with a fuller abdomen that becomes especially noticeable when they are carrying eggs. Attraction is achieved through a combination of pheromones and call-and-response gender-specific substrate‑borne vibrations. Both sexes drum their abdomens against the surface of a host plant, sending signals through the wood that help them locate one another.

Mating can last for several hours, with the male and female joined end‑to‑end while sperm is transferred. Although females feed on the trunk of a tree, they generally head upward to lay egg masses and research reveals that 80-90% of egg masses are found at 10 feet or higher – often on the underside of branches. After mating, the female searches for a place to lay her eggs—and she is not selective. Each female produces one to two egg masses, each containing 30 to 50 eggs. She coats the mass with a specialized waxy secretion that hardens into a gray, mud‑like smear, protecting the eggs through winter, but they are still vulnerable to extreme cold. Studies show increasing mortality below about 10°F, with near‑total die‑off when temperatures reach –13 to –15°F for extended periods. This coating also works brilliantly to camouflage them. The small red dot at the tip of the female’s abdomen is the end of her ovipositor, the egg‑laying organ, which remains slightly visible even when retracted.

Adult spotted lanternflies on a red maple in Berks County, Pennsylvania, mid-October 2019. Wikimedia Commons. Photo: Rkillcrazy. CC BY-SA 4.0

The early nymphal instars – an instar is a growth stage between molts in insects and other arthropods — are inconspicuous until the bright red fourth instar. Nymphs feed on a wider range of plants than adults and prefer tender new growth, leaves, and stems. Adults shift to woody plants and often congregate on trees with high sugar content.

Spotted lanternflies continue to evolve. There is evidence that they may have genetically learned a trick or two in China’s urban centers. Urban evolution in China appears to have “pre‑adapted” them for invasion: studies of Shanghai populations show that city living selected for genes tied to heat tolerance, pollution resistance, detoxification, and rapid reproduction, creating hardy urban insects that were already primed to survive the stresses of new environments long before they arrived in America. When scientists discuss “detoxification” in spotted lanternflies, they mean the insect’s ability to neutralize or tolerate the toxic chemicals in tree of heaven sap. The China study suggests that spotted lanternflies have the biochemical tools that could support pesticide resistance in the future, but it does not show that resistance is developing now. See the 2026 article “Cities as evolutionary incubators for the global spread of the spotted lanternfly” in Proceedings of the Royal Society B: Biological Sciences, 293(2064), 20252292.

Spotted lanternfly (Lycorma delicatula) 4th instar nymph (red body) in Pennsylvania, 20 July 2018. Wikimedia Commons. Photo: Stephen Ausmus, USDA. Public Domain

Do Spotted lanternflies have enemies? What eats them? In China, spotted lanternflies are kept in check mainly by tiny parasitic wasps that lay their eggs inside SLF egg masses, with the wasp larvae consuming the developing lanternflies. Unlike in the U.S., where birds and generalist predators occasionally eat the adults, these egg‑attacking wasps are the only consistently documented natural enemies in the insect’s native range, and they effectively bypass the lanternfly’s chemical defenses and warning coloration by targeting the vulnerable egg stage. In the U.S., spotted lanternflies are eaten by a broad diversity of opportunistic predators, however none suppress the population in a significant way. The most reliable dinners are praying mantises, spined soldier bugs, yellow jackets, orb weaver spiders, and wheel bugs, all readily attack nymphs or adults. Among vertebrates, chickens, ducks, and sometimes cats and dogs will eat them, and several backyard birds—especially gray catbirds, northern cardinals, blue jays, and tufted titmice—have been documented eating adults. An assortment of animals, including frogs, koi, goldfish, bats, squirrels, and garter snakes, consume them opportunistically. While the list may seem long, the U.S. predator community nibbles at lanternflies but doesn’t exert the strong, consistent pressure seen from egg‑parasitic wasps in the insect’s homeland.

Why is Something So Pretty Such a Problem

Spotted lanternflies are called many things—some unprintable—but almost never “ugly.” Once you get past the standard human bug‑revulsion, they’re surprisingly handsome at every stage. This is deeply inconvenient, because it makes them far too easy to admire while you’re trying to squash them. Once you get past the instinctive aversion to insects, they’re striking at every stage of their life cycle. And while a few species mimic their appearance, once you’ve spent any time searching for them online, they are easily recognized.

It helps to begin with a little myth‑busting. Penn State Extension did exactly this in a January 2022 post, Spotted Lanternfly Lore: Penn State Experts Clear Up Falsehoods About Pest. Here are three selected myths. Myth: Spotted lanternflies kill all plants and trees. In reality, they rarely kill their hosts. Grapevines are one notable exception, and the piece indicates that their feeding can also kill tree of heaven, although current research reveals this is unlikely to be the primary cause of death. What lanternflies can reliably cause is stress—enough to make trees more vulnerable to other pressures such as insects, disease, or drought, and enough to reduce growth. Myth: Homemade sprays are safe and effective. Dish soap, vinegar, glass cleaner, and similar mixtures can be harmful to plants, pets, and people. If you decide to use a chemical approach, you’re far better off choosing a registered insecticide and precisely following the label. Myth: Spotted lanternflies are harmful to humans, pets, livestock, or buildings. They don’t bite or sting, and they don’t damage structures. Even in large numbers, they’re more of a nuisance than a threat—though they’re not exactly palatable for most animals because of tree of heaven feeding.

What isn’t a myth is their ability to make being outdoors miserable. A heavy hatch can turn a pleasant afternoon into something that feels more like a low‑budget horror film.

Spotted lanternflies on grapevines at Waltz Vineyard, Manheim, PA, 29 August 2018. Wikimedia Commons. Photo: USDA. Public Doman

What’s on the Menu

More than 172 known hosts worldwide are on the menu! Get ready — you may be serving breakfast, lunch, and dinner. The spotted lanternfly (Lycorma delicatula) strongly prefers tree of heaven (Ailanthus altissima) when available, but it is capable of feeding on many different plant species and can utilize a wide range of hosts. Grapevines are among the most economically important hosts and are particularly vulnerable to heavy infestations. SLF also feeds on maples, black walnut, oaks, and many fruit trees, as well as ornamental species such as crape myrtle. Conifers other than pine are not used as feeding hosts. While spotted lanternflies primarily feed on woody plants with strong phloem flow, nymphs are more generalist and may probe a variety of herbaceous plants, though these do not support development. They do not consume fruit directly but instead feed on sugar‑rich phloem sap, which makes many orchard species suitable hosts. See Penn State Extension’s Common plant hosts for spotted lanternfly feeding throughout the season (Table 2) for a seasonal menu.

Lanternfly Season is Upon Us

I could have titled this section Now What Do I Do? Fortunately, we’re not navigating this stage—or the ones ahead—without help. Several excellent guides lay out what to expect and how to manage the onslaught headed our way. If you’re feeling perplexed, reviewing one of them is time well spent. See the section SLF Management: Suppression but Not Eradication farther along in this article for links to these resources. You may ultimately decide that chemical control is necessary, but if you go that route, timing and product choice matter. Being informed isn’t just about personal and environmental safety; it’s the difference between an effective treatment and a wasted effort.

March Through April

Central Virginia has one generation of spotted lanternfly each year. Adults laid eggs on many surfaces through fall 2025, and those eggs overwinter and begin hatching from mid‑April into early May. Early nymphs are black with white spots, progressing to the red fourth‑instar stage from late spring into August. March and April are your preparation window: keep checking for egg masses and destroy any you find, and decide early whether you’ll use traps—sticky bands and circle traps only work if they’re in place before nymphs start climbing.

If you have tree of heaven, a systematic systemic plan should include removing all female trees to prevent seed production and leaving a few male trees as treated “trap trees.” These male trees cannot produce seed but strongly attract lanternflies, which feed heavily and die after ingesting the systemic treatment. Encourage neighbors to participate as well. A systematic systemic plan likely means working with a licensed professional to apply a trunk‑injected or soil‑applied systemic insecticide to selected male trees. Ideally, the impact of this would then be monitored across several seasons.

By mid‑April into early May, the first nymphs appear—tiny black specks that hop and climb toward tender new growth. This stage lasts through June and is easy to miss if you’re not watching closely. By early July, fourth instars turn red with white spots and black patches. At this point, you can often remove a nymph by hand and squish it or drop it into soapy water or alcohol.

Current Virginia Cooperative Extension’s Best Management Practices for Spotted Lanternfly (2025) does not recommend traps. They were removed due to limited effectiveness and concerns about wildlife bycatch, even when sticky tape guards were used. The March 3–5, 2026 Spotted Lanternfly Summit (StopSLF.org) returned to topics on SLF biology, movement, monitoring tools, host‑tree management, agricultural impacts, and emerging biological‑control research. In SLF monitoring research and in prior Summit presentations, sticky bands have consistently been described as tools that primarily detect nymph activity rather than meaningfully reducing populations, and adults frequently avoid or escape them. Wildlife‑safe circle traps have repeatedly been shown in published studies and multi‑state extension trials to capture nymphs and adults more reliably while greatly reducing wildlife bycatch. In fact, earlier VCE outreach materials and county extension guidance recommended funnel‑style circle traps as a safer alternative to sticky bands, although the 2025 statewide Best Management Practices no longer include trapping as a recommended strategy. However, if a homeowner still chooses to use traps, this is the prime time to deploy them with great care. Sticky bands should only be used with mesh guards to protect wildlife, and they can be paired with funnel‑style circle traps. Wire guards are less safe because they behave like a rigid cage and can trap small mammals. Place traps about four feet up the trunk of a favored host tree and check them frequently. If you begin catching beneficial insects or small animals, adjust or remove the setup immediately. Never leave bands or traps in place once they are no longer needed. Clear weeds and low branches around host trees to eliminate staging spots.

Contact insecticides can be used during this period, but never spray when pollinators are active. And never apply neonicotinoids—imidacloprid or dinotefuran—to blooming plants. Nymphs are far easier to kill than adults, so early‑season action matters.

December through March

A window of opportunity is immediately preceded by eggs overwintering and hatching mid‑April through early May. Adults appear by late July and remain present through December, or until a hard freeze kills them. Egg‑laying begins in September and continues until cold weather ends the season. The entire cycle is explained in Virginia Cooperative Extension’s Identification and Life Cycle of Spotted Lanternfly in Virginia. For something a little different and with wonderful illustrations, see Molly Schafer’s (Mt. Cuba Center) The Life Cycle of the Spotted Lanternfly (24 October 2012).

Winter is for detective work, not insecticide spraying. Although VCE advises you can apply dormant oil or horticultural oil directly on egg masses higher up in tree canopies from mid-February to early April, beginning when overnight temperatures do not go below freezing the night after application. Do not use after budbreak in spring. Begin realizing that while winter was challenging this year, it did not solve our lanternfly problem. In a WSLS television report, Virginia Tech entomology professor Doug Pfeiffer says, “. . . lanternfly eggs are up on trees all the way along the whole heights of trees, so they won’t be getting much protection from snow.” And in the same feature, an exterminator advises hatches might be reduced but not eliminated at sustained temperatures of -10 to -30. These temperatures are far below what most of Virginia experiences. He doesn’t see it having much effect at all. So, we were left with viable egg masses everywhere—had we only taken the time to look. It’s the season to scout and scrape, even though most of those masses are probably tucked into places you’ll never reach. Before spring travel, clean bumpers, wheel wells, and truck beds; be creative, because lanternflies are. There is no evidence that a car wash or power-washer will remove eggs masses. If your property has tree of heaven, winter is also the perfect time to identify clumps and trunks for removal. Now we’ve cruised through March and, as I’m writing this, we’re in mid‑April.

Mid-April into June

Now let’s journey back from what’s past into what’s ahead. By mid‑April into May, the first‑instar nymphs begin to appear—tiny black specks with white spots that hop and climb toward the newest, tender growth. This stage runs through June, and if you’re not watching closely, you can miss most of the action. By early July, the fourth instars turn red with white spots and black patches. At this point, you can often remove a nymph from a plant and squish it or drop it into a jar of soapy water or alcohol, although Virginia Cooperative Extension does not recommend hand‑killing as a management strategy.

Repeating March – April guidance from above: Earlier guidance sometimes recommended sticky bands or circle traps, but the current Virginia Cooperative Extension Best Management Practices (2025) no longer includes traps due to limited effectiveness and concerns about wildlife bycatch. If a homeowner still chooses to use traps, they must be deployed with great care: sticky bands only with mesh or wire guards, and funnel‑style circle traps placed about four feet up the trunk of a favored host tree. Check traps frequently and remove or adjust them if they begin catching beneficial insects or animals. Clear weeds and low branches around host trees to eliminate staging spots.

By this point—certainly into May—it’s acceptable to prune low‑hanging branches where nymphs tend to gather. Contact insecticides or biological controls can now be used. VCE recommends contact sprays from mid-May to mid-July and fungal preparations can be applied early May to early June. Never spray when pollinators are active, and avoid applying neonicotinoids such as imidacloprid or dinotefuran to blooming plants. Once absorbed, these systemic chemicals move into the plant’s sap, killing sap‑feeding insects when they ingest it. Some leaf‑eating insects may also be affected depending on how the chemical moves within the plant.

July through August

Spotted lanternfly (Lycorma delicatula) face in the US, 22 October 2025. Wikimedia Commons. Photo: Alex Abair. CC BY 4.0

By late July, adult spotted lanternflies begin to appear. Their feeding can create dramatic scenes—large clusters gather on trees, and the honeydew they secrete coats leaves, trunks, outdoor furniture, and anything beneath them. Both nymphs and adults produce honeydew, but it becomes far more noticeable once adults arrive. Sooty mold quickly colonizes this sticky layer, which can further stress plants by blocking light and reducing photosynthesis.

If the sooty mold is bothersome, you can rinse trunks or surfaces with water, though this is mainly for aesthetics. You can spot‑spray adult aggregations using products specifically indicated for spotted lanternfly. To protect pollinators, avoid spray drift. Grape growers especially may need to use designated insecticides when populations are high. Remember, the current Virginia Cooperative Extension Best Management Practices (2025) does not include traps as a control method. However, if you choose this option (sticky tape or circle traps) will continue to capture some nymphs and adults as they climb. VCE recommends systemic insecticides mid-July to September.

If a plant is being heavily fed on, make sure it stays well‑watered. Adequate hydration helps reduce stress and supports recovery from feeding damage. Avoid unnecessary pruning during this period, as pruning adds additional stress to the tree.

Fall

Spotted lanternfly (Lycorma delicatula), Gillis Falls Park, Woodbine, Maryland, 10 September 2023. Wikimedia Commons. Photo: Judy Gallagher. CC BY 2.0

Now, after an irritating summer, imagine it’s fall—unfortunately, it’s no less disturbing. If your street is lined with maples or other favored hosts, you may see hundreds, even thousands, of lanternflies coating the trunks. Egg masses will be everywhere. It’s a full‑on SLF mating frenzy: adults feeding, pairing up, and females laying eggs on nearly any surface they can find. Stay vigilant. Freezing temperatures will eventually bring relief, but until then, keep up the management routine. Practice good travel hygiene. You don’t want to spread the problem to environments yet to be colonized. And, for next year, take note of where infestation was heaviest.

SLF Management: Suppression but Not Eradication

Begin with Virginia Cooperative Extension’s directory of resources Spotted Lanternfly in Virginia. VCE’s 2026 Pest Management Guide – Home Grounds and Animals is a basic resource and pay special attention to VCE’s Best Management Practices for Spotted Lanternfly in Yards and Landscapes (2025). Read this concise guide carefully. Its timing recommendations are used in what follows and in the preceding section. In the Pest Management Guide see the section “Home Ornamentals: Insects of Trees, Shrubs, Annuals, and Perennials”, 4-60. For grapevines see “Home Fruit: Disease and Insects”, 3-6. See also the Penn State Extension “Spotted Lanternfly Management Guide” (June 2024). Whenever confused, consult official Virginia Cooperative Extension publications and call the Piedmont Master Gardeners’ Horticultural Help Desk.

The Most Recent Overall Assessment

The March 2026 Spotted Lanternfly Summit—hosted by StopSLF.org, a multi‑state collaboration involving state agencies, university researchers, government representtives, and industry partners—considered agenda topics on SLF biology, movement, monitoring tools, host‑tree management, agricultural impacts, and emerging biological‑control research. Together these explorations illustrate how multiple approaches can contribute to integrated pest management. In the broader research literature, integrated management emphasizes combining mechanical tools, targeted insecticide use, and strategic management of tree of heaven to create localized population sinks while minimizing broad‑spectrum applications. A population sink is an area where SLF numbers decline faster than they can be replaced. Although the Summit has not published written proceedings or formal recommendations, its agenda highlights the breadth of ongoing work, and recordings of its sessions are available on the StopSLF.org website.

Scraping and Spraying Egg Masses

Do this from mid-February to early April. Spotted lanternfly egg masses are best destroyed from winter through early spring — after October when most laying is done, but before eggs hatch in late April or May. The masses look like small smudges of dried mud or putty, about 1 to 1.5 inches long, with a shiny gray waxy coating when fresh that weathers to a dull, cracked surface over time. Each mass holds 30 to 50 eggs, so every one you find and destroy makes a real dent in next year’s population. Check tree trunks, undersides of branches, rocks, outdoor furniture, vehicles, firewood, and any other hard outdoor surface — and where you find one mass, look for more nearby, since they tend to cluster. Ohio State University Extension provides excellent pertinent illustrations in its Spotted Lanternfly Update, Winter 2025/2026.

To destroy them, press a credit card, putty knife, or any flat tool firmly across the mass and crush it in place until you hear and feel the eggs pop. Or squirt some hand sanitizer or rubbing alcohol into a zip-lock bag, scrape the mass into it, seal, and trash it. Either way, firm pressure and full contact with alcohol are the keys.

Dormant and horticultural oils can be used on egg masses you can’t physically reach; both are petroleum‑based products that kill spotted lanternfly eggs by smothering them, making them among the least toxic chemical options available. Their main advantage is reach: because most egg masses sit high in the canopy, directing oil sprays at visible, out‑of‑reach masses from mid‑February through early April can kill up to about 75% of the eggs you hit. Dormant oil is heavier and must be applied before any budbreak, while horticultural oil is lighter and can be used later, though still not after budbreak. Both oils carry real risks if misused—applying them too late in the season, to drought‑stressed trees, or when overnight temperatures will drop below freezing the first night after application can cause phytotoxicity (leaf burn), including foliage burn and bark injury, and some species are sensitive enough that even a single application may cause damage. To reduce risk and improve effectiveness, spot‑spray directly at egg masses rather than broadly coating the trunk or canopy, which does not improve control and only increases the chance of plant injury.

Tree of Heaven Removal

Cooperative Extensions across affected regions urge the removal of tree of heaven as one strategy for suppressing spotted lanternfly populations. It’s important to recognize, however, that tree of heaven now grows far beyond residential landscapes, colonizing forests, highway margins, and other disturbed areas.

Numerous well‑prepared, richly illustrated guides outline effective approaches for managing this invasive tree. In most cases, achieving lasting control ultimately requires careful use of herbicides. Without herbicides, the tree’s aggressive “root suckering” response — a veritable hydra effect — will turn one trunk into a forest of dozens in a season. This is because the tree eagerly sends up roots from its lateral root system. Before beginning any removal effort, consult the detailed guidance provided by MSU Extension, the Virginia Department of Forestry, and Penn State Extension. See especially Invasive Plant Species: Ailanthus (Ailanthus altissima) by Karen Snape and the excellent video Killing Tree of Heaven: Why, How & When as well as Controlling The Tree of Heaven: Why It Matters.

Finally, a recently published Virginia Tech article reports that researchers are testing the naturally occurring fungus Verticillium nonalfalfae as a biological control capable of killing tree of heaven.

Sticky Tape Traps (Sticky Bands)

The 2025 VCE Best Management Practices does not mention tape, so while it is not prohibited neither is it recommended and the City of Charlottesville explicitly does not endorse or encourage the use of traps. If you choose this option, apply tape beginning in mid-April. Sticky bands are a popular and effective way to catch nymphs as they climb a tree, but they can harm climbing wildlife and occasionally pollinators. They work best from May through August, when nymphs are active. Adults are less reliably captured, although you will capture many. Sometimes they can pull themselves free once the tape has weathered. Choose a tree the lanternflies favor—if you don’t have tree of heaven, that’s often a maple. Wrap the trunk about four feet off the ground, making sure the tape is snug — otherwise SLFs will simply crawl underneath. This works best when bark is smooth.

To avoid harming non‑target creatures — this is critical — add a mesh guard, perhaps made from a strip of vinyl window screening. Secure it with pushpins and flare the bottom like a skirt. You can also cut the tape (usually two to four inches wide, sometimes wider) down to three inches. Some experts recommend reversing the tape — sticky side in and slightly away from the trunk — to reduce wildlife impacts while still catching nymphs. For an excellent video that shows how to use tape with mesh see Pennsylvania’s Lancaster County Conservation District’s Sticky Tape with Mesh Barrier for Spotted Lanternflies: How to Set Up. For replacing the tape — as well as maintaining traps — watch Tree Trap Maintenance for Spotted Lanternflies.

Circle Traps

The 2025 VCE Best Management Practices does not mention traps, so while it is not prohibited neither is it recommended and the City of Charlottesville does not explicitly endorse or encourage the use of traps. If you choose this option, apply beginning in mid‑April. You can make them yourself by forming a funnel of window screening around the trunk and attaching a collection bag at the top. As nymphs and later adults move upward they are guided into the bag and cannot escape. Pre‑assembled circle traps are also available if you prefer not to build your own. Circle traps now exist in several variations that all rely on the upward‑funneling principle. The classic design uses a screen funnel and mesh bag, while commercial versions use more durable materials, rigid funnels, and zippered chambers for easier installation. Research settings also use modified versions sized for vineyard posts or paired with attractants, and mesh‑based variants keep captured insects alive so their aggregation cues can help draw additional SLF into the trap. Experimental cone‑top or lampshade designs add textured interior surfaces intended to encourage females to lay eggs inside a removable chamber, though these remain under evaluation. See Rutgers Extension’s Management and Trapping Spotted Lanternfly. If you’d like to build your own circle trap, see Penn State Extension’s article How to Build a Spotted Lanternfly Circle Trap and Spotted Lanternfly Circle Trap. There are many videos on the web describing how to make DIY traps with a variety of materials.

Biological Controls

Biological control of spotted lanternfly focuses on tiny parasitoid wasps from its native range that attack eggs and nymphs, offering a potential path for long‑term population suppression. U.S. researchers are still testing these wasps for safety and host‑specificity, and none have been approved for general release yet. General predators like birds or mantises eat lanternflies occasionally but do not significantly reduce populations.

Natural pathogens also play a role in suppressing populations. VCE lists Venerate XC (containing the bacterium Burkholderia spp. strain A396) as a biological control option for use from early May to early June. While such biological and fungal preparations—including those containing the fungus Beauveria bassiana—are organic, they are typically slower-acting than chemicals. Furthermore, the effectiveness of fungal treatments, in particular, depends heavily on moisture and temperature. Other fungi occur naturally. The native fungus Batkoa major can cause “summit disease,” characterized by infected insects climbing upward before dying to better disperse spores. While researchers at Penn State and Cornell have identified the fungi — Batkoa major and Beauveria bassiana — as significant natural enemies, they do not yet provide reliable population control on their own. VCE prioritizes more established Integrated Pest Management (IPM) strategies—such as managing preferred host plants like the tree of heaven, destroying egg masses, and applying targeted contact or systemic insecticides during the appropriate windows.

Topical and Systemic Insecticides

Virginia Cooperative Extension recommends both contact and systemic insecticides for controlling spotted lanternfly. The 2026 Pest Management Guide (section 4‑60) notes that SLFs occur on plants from May through October and that treatments may begin in May and be repeated as needed. Contact insecticides—carbaryl, malathion, bifenthrin, and other synthetic pyrethroids such as tau‑fluvalinate—are applied as spot sprays to tree trunks, branches, and foliage where SLF are actively feeding, beginning in May and continuing into early July. Though they work by different mechanisms, all ultimately kill SLF by overstimulating the insect’s nervous system to the point of paralysis and death. Bifenthrin and other pyrethroids disrupt sodium channels in nerve cell membranes, causing nerves to fire uncontrollably, while carbaryl and malathion block the enzyme that normally clears chemical signals between nerve cells, with the same fatal result.

For organic control, VCE lists three options: insecticidal soap, natural pyrethrins, and neem oil. Natural pyrethrins kill SLF the same way synthetic pyrethroids do—by disrupting sodium channels and causing paralysis—but they break down rapidly in sunlight and air, so repeated applications are needed. Insecticidal soap works on contact by disrupting cell membranes, making it most effective on young nymphs. Neem oil works more slowly, interfering with the hormones that regulate molting and reproduction, acting as a feeding deterrent, and—at sufficient concentration—suffocating insects by blocking their breathing pores. Because SLF is highly mobile and residues from organic products dissipate quickly, repeated applications of all organic options are often necessary as new individuals move into treated areas. Apply from May through early July.

Systemic insecticides can be applied from mid‑July through September. The two products listed by Virginia Cooperative Extension—dinotefuran and imidacloprid—are absorbed into the tree’s vascular system and kill SLF when the insects feed on treated sap. Both are neonicotinoids, which overstimulate the insect nervous system by binding to nicotinic acetylcholine receptors, ultimately causing paralysis and death. They are relatively low in toxicity to people and other vertebrates, but highly toxic to bees and other beneficial insects, which is why VCE requires that they be applied only after the tree has finished flowering and not when flowering weeds are present within the root zone.

Systemics provide longer‑lasting protection than contact sprays and are especially valuable for large or tall trees that are difficult to spray thoroughly, or in situations where repeated contact treatments aren’t practical. Dinotefuran acts quickly—often within 24 hours of a trunk injection, for instance—making it well suited for midsummer through fall (mid-July to September) targeting of adults, while imidacloprid moves more slowly but tends to have a longer residual and is applied only after bloom, typically from late spring through July. Systemic treatments are used both to create “trap trees” from remaining male tree of heaven and to protect high‑value landscape trees from feeding damage. While homeowners can feasibly apply soil drenches or basal bark sprays, trunk injections for large or sensitive trees are best left to licensed professionals to ensure precision and safety.

Note that SLF does not need to appear on the insecticide label, but the treated plant does, so make sure the product is labeled for trees and shrubs, or for fruit and grapes if treating those crops. Avoid treating plants that are currently in flower to protect pollinators. In all cases, treat only where SLF are actively present rather than blanket-spraying an entire tree or yard. As with any pesticide, always read and follow the product label — the label is the law.

Finally, when using pesticides, always follow the instructions on the label and use personal protective equipment (PPE). North Carolina Extension’s David Birdsell’s video PPE Tips for the Gardener is an excellent introduction. Virginia Cooperative Extension’s 2026 Pest Management Guide includes PPE‑related safety guidance within “Chapter 1: Regulations and Basic Information,” under “Safe and Effective Use of Pesticides for Home Grounds and Animals.” PPE is addressed directly in sub-section 1‑14, though the entire section is comprehensive, clearly presented, and well worth reviewing.

The Homefront: The Charlottesville Area and Albemarle County

From Parks & Rec Charlottesville, as of this writing: “The City is not currently considering insecticide treatment due to the uncertainty of success and excessive costs; however, we may treat limited high-value trees if deemed necessary.” While the City would like to remove all Tree of Heaven trees “attempting to do so would not be operationally or financially feasible.” “The City does not endorse or encourage the use of traps to reduce SLF numbers.” It does encourage egg mass removal. And it advises: “Do not use pesticides at home unless you comply with all state and federal laws and apply products according to the label’s instructions.” Albemarle County maintains a web page linking to official resources. Albemarle County was placed under a spotted lanternfly quarantine by the Virginia Department of Agriculture and Consumer Services (VDACS) in 2021–2022, and the quarantine was removed in 2025 when VDACS lifted the statewide order because SLF had become widespread.

The Cultural Impact

The spotted lanternfly onslaught hasn’t just sparked a shared sense of purpose around suppression and eradication. It has also seeped into popular culture—sometimes earnestly, sometimes absurdly. You can now find everything from Halloween costumes, a Jimmy Kimmel segment, and house decorations to a Saturday Night Live sketch, and even Etsy shops selling SLF‑themed clothing and more. The insect has a full digital life on Reddit and TikTok.

It’s also shown up in fiction. See “The Lanternflies” by Arlaina Tibensky (The Dodge, no. 4, 2025), or Roy Isen’s “It’s War! Cicadas vs. Spotted Lanternflies” in Flash Fiction Magazine (30 August 2021). Tibensky uses a spotted lanternfly infestation as a backdrop for a narrative exploration of pregnancy, community anxiety, and the mix of rage and solidarity that develops during an invasive‑species crisis. Isen’s short work is a satirical exploration of human conflict, tribalism, and the futility of war. The video documentary Uninvited: The Spread of Invasive Species (2021) includes SLF. There’s even a reflective turn in Maria Rodale’s excerpt from Love, Nature, Magic: Shamanic Journeys into the Heart of My Garden (Chelsea Green, 2023), (“Lanternfly: The Way to Heaven Is Through Joy”), in which she describes killing lanternflies on a tree of heaven and then embarking on a spiritual journey to commune with one. And yes—there’s even a New York Times piece highlighting SLF sympathizers: “In the Lanternfly War, Some Take the Bug’s Side” by Sarah Maslin Nir (24 August 2022).

An interesting SLF novelty is “SLF honey” for human consumption. Penn State Extension advises: “Honey made from spotted lanternfly honeydew has a distinct smokey odor. The color is dark brown but not nearly as dark or black as buckwheat honey. The honeydew honey is not as sweet as other kinds of honey and has a lingering aftertaste.” It can be purchased—search online for brands. Penn State Extension goes on, “Yes, honeydew honey is safe for both bees and humans to consume. Preliminary results of laboratory testing show that the levels of pesticides from lanternfly treatment efforts found in honeydew honey are exceedingly small and well below any level of concern. In addition, beekeepers in areas where lanternflies have been established for several years see that honey bees overwinter very well on this type of stored food.”

PESTICIDE WARNING

Pesticides (which include herbicides, insecticides, rodenticides, etc.) are poisonous. Always read and carefully follow all precautions and safety recommendations given on the container label. Store all chemicals in the original labeled containers in a locked cabinet or shed, away from food or feeds, and out of the reach of children, unauthorized persons, pets, and livestock. Consult the pesticide label to determine active ingredients, signal words, and proper protective equipment. Pesticides applied in your home and landscape can move and contaminate creeks, lakes, and rivers. Confine chemicals to the property being treated and never allow them to get into drains or creeks. Avoid drift onto neighboring properties and untargeted areas.

Featured Image: Since hatching doesn’t happen all at once, different life stages overlap and appear simultaneously. This is an adult with a 4th instar nymph, Pennsylvania. 30 July 2018. Wikimedia Commons. Photo: U.S. Department of Agriculture. Public Domain

Selected Sources and Practical Applications

Acimovic, Srdjan, Shawn D. Askew, Eric R. Day, Alejandro Del-Pozo, Jeffrey F. Derr, Carrie Fearer, Daniel Frank, Chuan X. Hong, David S. McCall, Dini M. Miller, Mizuho Nita, James A. Parkhurst, Sally L. Paulson, Douglas G. Pfeiffer, Kevin, B. Rice, Steven L. Rideout, Sutton, Kemper, James Wilson, Stephanie Blevins Wycoff. 2026 Pest Management Guide – Home Grounds and Animals. Publication 456-018. Virginia Cooperative Extension.

Day, Eric, Mark Sutphin, Theresa A. Dellinger, and James Mason. “Best Management Practices for Spotted Lanternfly in Yards and Landscapes.” Revised 16 October 2025.. Virginia Cooperative Extension. Available as a PDF.

Day, Eric, Theresa A. Dellinger, Doug Pfeiffer, and Mark Sutphin. “Identification and Life Cycle of Spotted Lanternfly in Virginia.” 2012. Virginia Cooperative Extension. Available as a PDF.

Dellinger, Theresa A., Eric Day, Mark Sutphin, and James Mason. “Homeowner Suggestions for Managing Spotted Lanternfly.” Publication ENTO-586NO. 9 October 2025. Virginia Cooperative Extension.

Duke, Amy. “Spotted Lanternfly Lore: Penn State Experts Clear Up Falsehoods About Pest.” Penn State Extension.

Goldsmith, Amanda. “Sticky Tape with Mesh Barrier for Spotted Lanternflies: How to Set Up..” Video. Lancaster County [Pennsylvania] Conservation District.

Goldsmith, Amanda. “Tree Trap Maintenance for Spotted Lanternflies.” Video. Lancaster County [Pennsylvania] Conservation District.

Harrison, Tim, Julie Crick, and Deborah McCullough. “A Tale of Two Invaders: Tree of Heaven and Spotted Lanternfly.” Bulletin E3486. East Lansing: Michigan State University, MSU Extension.

Jackson, David R., Sarah Wurzbacher, and Art Gover. “Tree-of-Heaven.” Penn State Extension.

Leach, Heather, Emelie Swachamer, Amy Korman, and Brian Walsh. “Spotted Lanternfly Management Guide.” Penn State Extension.

Meng, F., A. A. Snead, A. Y. Zhang, J. Munshi-South, and K. M. Winchell. “Cities as Evolutionary Incubators for the Global Spread of the Spotted Lanternfly.” Proceedings of the Royal Society B: Biological Sciences 293, no. 2064 (2026): 20252292.

Neur, Catherine. “The Tree That Still Grows in Brooklyn, and Almost Everywhere Else.” The Gotham Center for New York City History, January 4, 2018.

Nir, Sarah Maslin. “In the Lanternfly War, Some Take the Bug’s Side.” New York Times, August 24, 2022.

Oten, Kelly. “Spotted Lanternfly.” North Carolina State Extension.

Penn State Extension. “Controlling Tree of Heaven: Why It Matters.” Video. Penn State Extension.

Penn State Extension. “Spotted Lanternfly.” Penn State Extension.

Penn State Extension. “Spotted Lanternfly Circle Trap.” Video. Penn State Extension.

Penn State Extension. “Spotted Lanternfly Management Guide.” June 2024.

Pfeiffer, Douglas G., Eric R. Day, Theresa A. Dellinger, and Mark Sutphin. “Spotted Lanternfly in Virginia Vineyards: Lycorma delicatula (White).” Publication ENTO-323NP. Virginia Cooperative Extension.

Piedmont Master Gardeners. “The Spotted Lanternfly Is Here. What Should I Do?” Piedmont Master Gardeners.

Rutgers Extension. “Management and Trapping Spotted Lanternfly.” Rutgers Extension.

Schmidt, Maddy. “Could Spotted Lanternflies Be a Good Thing?” Peril & Promise, PBS, August 17, 2022.

Seifrit, Donald. “How to Remove Spotted Lanternfly Eggs.” Video. Penn State Extension.

Snape, Karen. “Invasive Plant Species: Ailanthus (Ailanthus altissima).” Virginia Cooperative Extension.

StopSLF.org. “Funding was provided by the Northeastern IPM Center to form a working group in summer of 2018 with Penn State as the lead institution. The working group met several times and submitted a successful proposal to the USDA-NIFA Specialty Crop Research Initiative in December 2018 to study the biology, ecology, and management of spotted lanternfly. The goals for this project are to develop efficacious tactics for managing the invasive spotted lanternfly (SLF, Lycorma delicatula) on vulnerable specialty crops to reduce the risk of widespread, catastrophic damage and to develop strategies for long-term SLF management. Our partnership includes seven universities, USDA-ARS, and APHIS, and will be advised by an engaged and thoughtful stakeholder advisory panel.” The organization maintains the “Spotted Lanternfly Literature Bibliography through 2024 (with additional A, altissima publications).” Available as a PDF.

Swackhamer, Emelie, Amy Korman, Heather L. Leach, and Joseph A. Francese. “How to Build a Spotted Lanternfly Circle Trap.” Penn State Extension.

Underwood, Robyn. “Spotted Lanternflies and Beekeeping.” Penn State Extension.

United States Department of Agriculture, Animal and Plant Health Inspection Service. “Spotted Lanternfly.”

Virginia Department of Forestry. Control and Utilization of Tree-of-Heaven: A Guide for Virginia Landowners. 2019. Available as a PDF.

Virginia Forest Landowner Extension Program. “Killing Tree of Heaven: Why, How & When.” Video.

Virginia Tech Department of Entomology. “Current Distribution of Spotted Lanternfly in Virginia.”

Wikipedia. “Spotted Lanternfly.”

How do vines fit into the landscape?

Pat Chadwick — Fri, 01 May 2026 15:27:19 +0000

Typical landscapes are designed in layers. The topmost or canopy layer consists of tall trees and large shrubs. The understory or middle layer is comprised of smaller trees and shrubs. The ground-hugging layer typically includes herbaceous perennials, annuals, and bulbs. So where do vines fit into this layered structure?

Vines are typically used to provide vertical interest in the landscape. Their role is to fill in the gaps between plants near the ground level and those in the understory and canopy layers of the landscape. Some of the longer vine species can climb up into the tallest trees, whereas some shorter or more diminutive vines sprawl or trail horizontally along the ground.

Besides providing color, texture, mass and vertical interest, vines also serve a functional purpose in the landscape. Depending on the vine species grown, they can provide shade or serve as a privacy screen to help hide trash cans, utility boxes, or other unsightly features from view. Flowering vines offer nectar and pollen for beneficial insect species. Birds often nest in vines and other small wildlife species can take refuge from the elements or seek safety from predators in a vine’s dense foliage.

BOTANICAL CHARACTERISTICS OF VINES

Vining plant species vary widely and may be woody, herbaceous, evergreen, or deciduous. Some vines are valued for their colorful floral displays. Others are grown for their foliage. Regardless of their obvious growth habits, vines exhibit several unique botanical characteristics that set them apart from other plant categories:

They are scandent. Broadly defined, this means they evolved to climb, lean, or sprawl in their attempts to reach sunlight.
They grow fast, with some reaching impressive heights in a very short time. As one extreme example, kudzu (Pueraria montana) can grow a foot per day.
They typically have weak, flexible stems that need support of some sort to help them grow vertically.
They don’t normally take up much space at ground level, but some can become quite massive as they grow upward and spread.
Most vines have specialized botanical features that help them grasp, twine, or adhere.

VINE CLIMBING FEATURES

Vines grow toward the light by using a variety of climbing strategies:

Tendrils. Botanically, these slender, flexible coiling organs are modified stems or leaves. When stimulated by touch (a process called thigmotropism), tendrils grab a point of contact such as a trellis, another plant, or even another stem from the same plant. At the point where the tendril makes contact, it exhibits low levels of auxins (phytohormones), which control stem elongation and directional growth. Auxin levels on the opposite side of the tendril are high, triggering those cells to grow longer causing the tendril to curve and form into coils. Passionflowers (Passiflora incarnata) and sweet peas (Lathyrus odoratus) are examples of vines equipped with tendrils.
Sweet Pea Vine. Photo Credit: Missouri Botanical Garden Plant Finder
Twining stems. Instead of grabbing a point of contact like a tendril, a twining stem coils itself around a support. Morning glories (Ipomoea species), purple hyacinth beans (Lablab purpurea), and honeysuckle (Lonicera species) are examples of vines with twining stems. Fun fact: According to Linda Chalker-Scott, author of How Plants Work, some vines twine in a clockwise direction but more than 90% of vine species twine counterclockwise, forming a right-handed spiral. The botanical term for this elliptical twining motion is circumnutation. If you unwind a flexible young vine stem and then rewind it in the opposite direction, the stem will try to unwind itself in its effort to return to its original direction.
Purple hyacinth bean Vine. Photo Credit: Pat Chadwick
Rooting stems. Also called adventitious or aerial roots, these structures form along a vine’s stem above the surface of the soil and are therefore exposed to the air. They securely attach the vine to whatever surface it is climbing. Poison ivy (Toxicodendron radicans) and climbing hydrangea (Hydrangea anomala) are two examples of vines that use this particular climbing strategy.
Poison Ivy. Photo Credit: Pat Chadwick
Adhesive pads. Also called adhesive discs or holdfasts, these features occur at the tips of some specialized tendrils and develop when the tendril touches a surface, such as brick, stone, a wall or tree bark. Contact with the surface stimulates cells at the tip of the tendril to divide and grow, forming a callus-like growth. The growth ultimately forms into an adhesive pad capable of adhering tightly to whatever it touches. Boston ivy (Parthenocissus tricuspidata) and Virginia creeper (Parthenocissus quinquefolia) are examples of vines with adhesive pads or discs.
Virginia creeper. Photo Credit: Missouri Botanical Garden Plant Finder
Thorns and thorn-like structures. Although not very effective as climbing devices, thorns or prickles do help some vine species, such as climbing/rambling roses, greenbrier (Smilax rotundifolia) and Bougainvillea, latch onto other plant growth as they climb. Mile-a-minute vine (Persicaria perfoliata) stems have hooked barbs, which are more effective than thorns in aiding the vine to climb over other plants and vertical supports.
Greenbrier. Photo Credit: Missouri Botanical Garden Plant Finder

TIPS FOR SELECTING VINING PLANTS

Vining plants can be tricky to select for the landscape. Part of the problem is that vines typically have a small footprint at ground level but as they grow upward, they can spread and take up a great deal of room. So, it’s really important to keep the plant’s mature size in mind when selecting a vine and how its size might affect nearby plants.

Vines can also be tricky to select because many require a support structure, which can add expense and effort. Unless you plan for the vine to spread across a fence, or up a tree or even the side of your house, you may need to install a sturdy trellis to support the weight of the vine. American wisteria (Wisteria frutescens), for example, is a woody vine that can grow to be very heavy, requiring a very sturdy trellis to support its weight.

Before investing in a vine, make sure you have a clear concept in mind. For example:

What type of vine do you want? Deciduous, evergreen, herbaceous (annual or perennial), or woody?
Will it require a trellis? If so, how tall and wide does it need to be? Think in terms of the vine’s mature size. A 6’ tall trellis, for example, won’t support a vine that grows 10’ tall.
Is the allocated space wide enough to accommodate the vine? This is particularly important to know if you’re considering a long-lived woody vine that may take up a lot of space.
As it stretches up, will the vine grow into nearby trees or shrubs?
Will it block access on nearby walkways?
Will it block sun from nearby plantings?
How much sun will it need? In other words, should it be a sun-loving or shade-loving plant?
How will it fit into your existing landscape? Will it harmonize with nearby plantings, dwarf them or encroach on them?
Other than being decorative, will it be used for a practical purpose, such as screening trash cans or for privacy?
How much maintenance will the vine require? Some vines require regular pruning to contain their overall size, or reduce the weight of heavier, woody species, or enhance flowering.

Once you have addressed those questions, research potential vine choices to make sure they match the criteria you have identified. Choosing a specific species is your first step. Keep in mind that growth habit, blossom color, foliage shape, or size of a cultivar or variety may differ from the straight species.

EXAMPLES OF VINES SUITABLE FOR MID-ATLANTIC GARDENS

If you want to experiment with vines but don’t want to make a long-term commitment, consider growing an annual vine such as:

Black-eyed Susan vine (Thunbergia alata) – Climbs 6’ to 8’ by twining.
Cardinal vine (Ipomoea x sloteri). Climbs 6’ to 12’ by twining
Cup and saucer vine (Cobaea scandens). Climbs up to 20’ using tendrils.
Mandevilla (Mandevilla species). Climbs up to 20’ by twining
Moonflower (Ipomoea alba). Climbs up to 20’ by twining
Purple hyacinth bean (Lablab purpureus). Climbs up to 15’ by twining.
Snail vine or corkscrew flower (Vigna caracalla). Climbs 12’ to 30’ by twining.
Sweet pea (Lathyrus odoratus). Climbs 3’ to 8’ using tendrils.
Sweet potato vine (Ipomoea batatas). Technically not a vine, this ornamental plant typically spreads horizontally to fill an area of about 3’. It can also be trained onto a trellis for a vertical effect.

Of the many perennial vines available, a few native suggestions include:

American wisteria (Wisteria frutescens). Less aggressive and slower growing than its non-native Asian relatives. It climbs by twining from 25’ to 40’ and blooms on new spring growth. Prune back yearly in fall to late winter to control its size.
American wisteria. Photo Credit: Missouri Botanical Garden Plant Finder
Crossvine (Bignonia capreolata) uses tendrils to climb 15’ to 50’, depending on the species or cultivar, and blooms on old wood. Prune immediately after it finishes flowering to avoid removing next year’s flower buds.
Crossvine. Photo Credit: John Ruter, University of Georgia, Bugwood.org
Passionflower vine (Passiflora incarnata) uses tendrils to climb 10’ to 15’ and may sucker aggressively. It is the host plant for the variegated fritillary butterfly. Bumblebees love it as well.
Passionflower vine. Photo credit: Missouri Botanical Garden Plant Finder
Pipevine or Dutchman’s pipe (Aristolochia macrophylla) climbs 20’ to 40’ by twining. It is a caterpillar host for the pipevine swallowtail butterfly (Battus philenor).
Pipevine. Photo Credit: Missouri Botanical Garden Plant Finder
Trumpet, or coral, honeysuckle (Lonicera sempervirens) climbs 10’ to 20’ vine by twining. Prune it in autumn or late winter. Flowers appear on the year’s new growth. It is a good choice for growing along a fence.
Coral honeysuckle. Photo Credit: Missouri Botanical Garden Plant Finder
Virginia creeper (Parthenocissus quinquefolia) grows 5’ to 40’ and climbs by tendrils which end in adhesive discs. It displays intense red foliage in autumn and is a host plant for Virginia creeper sphinx moth and Achemon sphinx moth larvae.
Virginia creeper. Photo Credit: Missouri Botanical Garden Plant Finder

AVOID INVASIVE VINES

Although garden centers are becoming more careful about not selling invasive species, occasionally you may find one for sale. Invasive vine species can outcompete native species by climbing over and smothering them, girdling them, blocking the sun from them, or crowding out young native seedlings. Some examples of invasive vines to avoid include:

Asiatic bittersweet (Celastrus orbiculatus)
English ivy (Hedera helix)
Japanese honeysuckle (Lonicera japonica)
Porcelain berry (Ampelopsis brevipedunculata)
Wintercreeper (Euonymus fortunei).
Wisteria (Chinese and Japanese varieties).

Featured Photo: Lonicera sempervirens ‘Major Wheeler’. Photo: Pat Chadwick

SOURCES:

How Plants Work (Chalker-Scott, Linda, 2015)

Vertical Gardening (Fell, Derek, 2011)

Annual Flowering Vines, Iowa State University Extension and Outreach

Climbing Vines in Coastal Virginia, James City County Williamsburg Master Gardener Association (By Elizabeth McCoy, Updated February 18, 2026).

Edible Landscape Species — Shrubs, Vines and Groundcovers, Virginia Cooperative Extension Publication SPES-317

Selecting Landscape Plants: Ornamental Vines, University of Missouri Extension

Perennial Vines: Friend or Foe?, PennState Extension

Illustrated Glossary of Horticultural and Botanical terms, Master Gardeners of Northern Virginia

Vine Selections for Landscaping, Clemson Cooperative Extension

Vines, University of Illinois Extension

The Ornamental Garden in May

Pat Chadwick — Fri, 01 May 2026 15:22:30 +0000

It’s May and frosty nights are now a distant memory, but the hot weather that descended upon us in April is probably foremost in every gardener’s mind. You’ll probably want to keep an eye on long-term weather forecasts in planning your gardening tasks this month. If there’s rain in the forecast, tasks like planting, dividing and transplanting become much more doable. Take a look at the various forecasts available at the National Weather Service’s Climate Prediction Center/Outlook Maps, Graphs and Tables, which include both long- and short-term forecasts — everything from the next month, the next few days, to the entire season. Besides planting and transplanting, there’s plenty of weeding, dividing, and general sprucing up to be done in the ornamental garden.

Short-toothed or clustered mountain mint. Missouri Botanical Garden Plantfinder

With so many plant choices available to you at this time of year, look for drought-tolerant selections that will require less water once the usual hot mid-summer weather arrives. Some potential candidates include black-eyed Susan (Rudbeckia), blanket flower (Gaillardia), butterfly weed (Asclepias tuberosa), catmint (Nepeta), goldenrod (Solidago), hyssop (Agastache), mountain mint (Pycnanthemum), purple coneflower (Echinacea purpurea), sneezeweed (Helenium), Stokes’ aster (Stokesia laevis), and yarrow (Achillea millefolium). Important: Although these plants are drought tolerant, they require ample moisture their first year while they are getting established.

With our last average frost date behind us, it’s now time to direct sow seeds of heat-loving annuals such as cosmos, marigolds, cleome, gomphrena, or zinnias. After the plants reach 4 to 6 inches in height, pinch them back to promote bushier growth. This will ultimately produce more flowers. For detailed guidance on seeding and maintaining annuals, see the new publication, “Annual Flowers: Culture & Maintenance,” Va.Coop.Ext. Pub. No. 426-200 (Apr.2026).

Transplant bedding plants on a cool, calm, cloudy day. The cooler temperatures and cloud cover will cause less stress to the plants and will help them settle in sooner. Some common fast-growing annuals that are sold as bedding plants include celosia, dusty miller, geraniums, lantana, lobelia, petunias, portulaca, salvia, and begonias.

Plant tender bulbs such as dahlias, gladioli, or cannas in full sun. If you don’t have full sun (at least 6 hours per day), try planting shade-loving caladiums and tuberous begonias. For a touch of drama, try growing elephant ears in part-shade but give them plenty of room. Depending on the variety, they can grow seriously huge!

Install supports for fast-growing plants that tend to flop. Secure tall plants such as delphiniums or foxgloves to a single stake using jute or other soft twine. For mounding plants such as peonies, use “grow-through” ring or grid-style supports.

Protect newly-planted seedlings and transplants from drying wind and hot sun for the first few weeks while they establish strong root structures. Keep the soil around the fragile roots moist but not soggy. If the root ball dries out, the plant may not recover from the stress. Too much water is just as bad for seedlings and transplants because soggy soil may cause their roots to rot.

Monitor moisture requirements of newly-planted trees. In general, it takes 2 to 3 years or more for a tree to become established in the landscape. Adequate moisture is particularly critical during this period to encourage healthy root development beyond the original root ball. In the absence of good soaking rains, provide supplemental water, particularly as daytime temperatures grow hotter. Cover the entire area under the tree canopy to keep the soil evenly moist but not soggy around the root ball and surrounding soil.

Prune spring-flowering shrubs after they finish blooming. If you put off doing this until later, you run the risk of cutting off the buds for next year’s blooms. Virginia Cooperative Extension (Va. Coop. Ext) Publication 426-701, Shrubs: Functions, Planting, and Maintenance, provides guidance on the best time of year to prune shrubs.

Lightly fertilize azaleas and rhododendrons after they finish blooming if a soil test indicates that nutrients in the soil are low. Use a fertilizer that is specially formulated for acid-loving plants and follow the directions carefully. Lightly scatter the fertilizer at the edge of the root zone. Azaleas have delicate roots that are close to the soil surface and can be easily burned by excess fertilizer. Too much fertilizer may also cause scorched leaf margins.

Finish acclimating your houseplants to the outdoors by gradually increasing their exposure to sunlight. Monitor them carefully so that they don’t become sunburned. Make sure each pot has a drainage hole. Lack of good drainage is an invitation for root rot.

Experiment with container gardening if you’ve never tried it before. For best results, keep in mind the “thriller, filler, spiller” concept: plant something tall as a focal point, something mid-size to fill in around the “thriller,” and something low that cascades over the rim of the pot and softens the overall effect. Just remember to keep container gardens well watered over the growing season.

Monarch visiting a butterfly weed. Photo: Cathy Caldwell

Incorporate pollinator-friendly plant species that attract bees, flies, butterflies and other pollinating insects to your ornamental garden. Some of these pollinator magnets are also drought tolerant, and one excellent example is the deer-resistant butterfly weed (Asclepias tuberosa). Flowers with single petals rather than double petals are generally a good choice. Echinacea (coneflower) and zinnias are examples of plants that have undergone significant breeding for fuller, showier flowers. While they offer more variety and pizzazz for the garden, the downside is that such breeding efforts affect the flower’s ability to produce pollen. In order to produce double flowers, the stamens (male portion of the flower) are bred to transform into extra petals. Because of this alteration to the basic anatomy of the flower, the blossom may not produce as much pollen as a flower having single petals.

Replace mulch with ground covers in your landscape. Mulch is useful in holding moisture in the soil, moderating soil temperatures, preventing erosion, and controlling weeds. However, in certain situations, such as under trees where grass struggles to grow in the shade, a living ground cover instead of mulch may be a more practical solution. Like mulch, ground covers shade the soil, hold it in place, and smother weeds. On top of the practical aspects of ground covers, they add an attractive layer of color and texture in the landscape. Consider planting native ground covers such as: wild ginger (Asarum canadense), green and gold (Chrysogonum virginianum), Allegheny spurge (Pachysandra recumbens), foamflower (Tiarella cordifolia), blue-eyed grass (Sisyrinchium angustifolium), and creeping phlox (Phlox stolonifera).

Blue-eyed grass. Photo: Cathy Caldwell

Monitor your prized plantings for pests of all kinds – creeping, crawling, flying, etc. For quick access to a variety of helpful resources about pests, see Garden Insect Pests, www.pubs.ext.vt.edu. Here are a few to be on the alert for in May:

Aphids – These voracious insects have mouth parts that are designed to pierce and suck the sap from a plant. They damage plants by causing yellowing, stunted growth, mottled leaves, browning, and even plant death. Ladybugs and lacewing larvae are the natural predators of aphids and may control them for you. If not, then a sharp spray of water is usually sufficient to dislodge aphids from plants. See Aphids in Virginia, Va.Coop.Ext.
Slugs – These nocturnal members of the mollusk family can do a lot of damage in just one night – especially to hostas. To eliminate these slimy creatures, take a flashlight outside after dark, hand pick any slugs you find (wearing gardening gloves, of course), and drop them into a container of soapy water. If that approach doesn’t appeal to you, sprinkle finely crushed eggshells around vulnerable plants. Slugs don’t like crawling over the sharp edges. Another approach is to use a shallow dish filled with beer to entice slugs. Any brand of beer will do. Just nestle the dish into the soil leaving about half an inch of the rim exposed above ground. The slugs crawl into the dish and drown in the beer. End of problem. The University of Minnesota Extension’s website offers advice on controlling slugs.
Ticks – Ticks are arachnids rather than insects and are at their most active between May and July. During this time, wear light colors, closed-toe shoes, socks, long pants and long sleeves when working outdoors. Don’t forget to tuck pant legs into socks. Check yourself, your children, and your pets after you or they have spent time outdoors. For a description of the primary types of ticks found in Virginia, see VCE publication 2906-1396 “Common Ticks of Virginia.”
Eastern Tent Caterpillars are the larval form of an ordinary looking yellowish-tan to brown moth (Malacosoma americanum). The hairy larvae hatch out in spring at which time they spin unsightly “tents” of silk webbing where they spend their nights. They emerge from the tents in the daytime to feed on the host plant, stripping it of its foliage. Insecticides are generally not effective when tent caterpillars are inside their tents. VCE publication 444-274, Eastern Tent Caterpillar offers more information on this insect. While tent caterpillars can be destructive to trees and shrubs, they are also an important food source for some bird species. Before deciding to kill the larvae, check out Entomologist Michael J. Raupp’s Bug of the Week website which provides useful information on tent caterpillars. While not many bird species will eat hairy caterpillars, the yellow-billed cuckoo is one bird species that will, according to Cornell University’s All About Birds.

Bad bugs get all the press but there are far more good bugs than bad, including:

Praying Mantis — Praying mantids are generally considered to be beneficial; but, unfortunately, mantids make no distinction between bad bugs and beneficial ones and eagerly gobble up both. If you spot the large Chinese mantid, be aware that it consumes a large number of beneficial pollinators and other native species including small birds, reptiles and amphibians as well as the smaller native Carolina mantis. Learn more about mantids in this recent Garden Shed article: Praying Mantids: Friend or Foe?
Syrphid fly. Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Syrphid Fly (Sphaerophoria philanthus) – Syrphid flies (also called hover flies or flower flies) serve double duty as both pollinators of a wide variety of plants and predators of other insects. These small black and yellow-striped insects measure less than ½ inch long and are often mistaken for bees or wasps. However, Syrphid flies don’t have stingers and, like all fly species, they have only one pair of wings, whereas bees and wasps have two pair. In their adult form, syrphid flies feed only on pollen, nectar and aphid honeydew and do not prey on other insects. As larvae, they are highly effective natural enemies of aphids, scales, thrips, and other soft-bodied, slow-moving insect species. Just one larva can consume hundreds of aphids. For photos of both the adult and larval forms of this beneficial insect, see North Carolina State University Extension’s publication on Syrphid Flies.

Take preemptive steps to keep deer out of the garden. As beautiful as deer are, they can do a devastating amount of damage to plants that are just emerging or leafing out. A tall fence or other physical barrier is the most effective way to keep deer out of your garden. If a fence is out of the question, then try growing plants with strong scents (such as herbs), tough or leathery foliage, and spiky or spiny foliage. Confuse deer by tucking vulnerable plants in among plants they normally shun. Use repellents that either smell or taste bad to deer. Repellents that have a sulphur-based odor of rotten eggs appear to be more effective than taste-based ones but alternate their use so that the deer don’t become accustomed to them. To learn more about deer and strategies for living with them, see Garden Shed article Deer, Deer, Deer!, which provides lots of great information on the subject.

Invasive Alert: Keep an eye out for the following invaders when you’re weeding your garden: English ivy (Hedera helix), climbing euonymus (Euonymus fortunei), Japanese honeysuckle (Lonicera japonica), Oriental bittersweet (Celastrus orbiculatus), Japanese barberry (Berberis thunbergia), autumn olive (Elaeagnus umbellata), wineberry (Rubus phoenicolasius), and garlic mustard (Alliaria petiolata).

SOURCES:

Featured Photo: by Cathy Caldwell

Monthly Gardening Tips, Piedmont Master Gardeners/Gardening Resources/May

Horticultural oils

Chris Stroupe — Fri, 01 May 2026 15:29:23 +0000

Horticultural oils are powerful tools that, in my humble opinion, aren’t employed by enough gardeners – myself included. My hunch is that the confusing, overlapping nomenclature surrounding horticultural oils is a hindrance to adoption. This article, then, will discuss how horticultural oils work, how they’re made, the meanings of the various terms describing them, and how to effectively and safely use horticultural oils in gardens and landscapes.

What are horticultural oils?

Soft-bodied insects like aphids are good targets for horticultural oils. Photo: Luis Fernández García. CC BY-SA 2.1 Spain

Horticultural oils are insecticides, miticides, and to a lesser extent fungicides. They work by forming a physical barrier that prevents air from reaching their targets. They also cause dehydration, by disrupting insects’ and mites’ protective waxy cuticle. They can prevent insect feeding and egg deposition by changing the taste and/or texture of leaves. Finally, horticultural oils can kill insect and mite eggs.

Virtually all commercially-available horticultural oils, with the exception of neem oil, are derived from petroleum. These oils are highly refined and filtered to remove phytotoxic, i.e. plant-damaging, components. They’re then mixed with emulsifying agents to disperse evenly in water.

Mites – which caused this boxwood damage – are another excellent target for horticultural oils. Photo: SB_Johnny. CC BY-SA 3.0 (cropped)

Vegetable oils like cottonseed oil – sometimes claimed to be the most effective plant-based horticultural oil – and soybean oil can be used as horticultural oils. Be cautious, though: their manufacturing processes aren’t designed to remove phytotoxic chemicals.

Horticultural oils work by direct contact with their targets, and they have low residual activity. In other words, an insect won’t be harmed by crawling on or eating a plant that had been treated with a horticultural oil; they simply don’t pick up enough of the oil to be affected. Moreover, horticultural oils evaporate quickly in warm weather and are easily washed away by rain or irrigation.

Integrated Pest Management, or IPM, matches assessed problems with minimal solutions. From Virginia Cooperative Extension document “An Introduction to Integrated Pest Management.”

Their low residual activity means that horticultural oils can be applied precisely when and where there’s a problem, with few harmful spillover effects. This makes horticultural oils a great addition to an Integrated Pest Management (IPM) regimen, as described in this article by Piedmont Master Gardener Cathy Caldwell. The basic idea behind IPM is to use the minimum intervention needed to reduce a problem to an acceptable level.

Terminology

Horticultural oils have been used for decades, if not centuries. Their manufacture has been fine-tuned over the years to reduce phytotoxicity, and this has changed how they are used. Their nomenclature, however, has not been updated, so it’s important to understand how these older terms relate to modern formulations and applications.

Dormant oils are oils applied during the dormant season, usually in late winter or early spring before buds open. Historically, dormant oils were heavier, less-refined products that were phytotoxic if used during warm weather or on foliage. Modern horticultural oils are more highly refined, so the term “dormant oil” now often refers more to the timing and application rate than to a fundamentally different kind of oil. Many modern horticultural oils can be used during the dormant season, and some products labeled for dormant use may also be used during the growing season at lower rates. Always follow the product label, since dormant-season applications are usually mixed at higher concentrations than in-season rates.
Summer oils are used during warmer months. Back in the day, these were highly refined oils that didn’t harm plants in hot weather. Today, their composition isn’t meaningfully different from dormant oils.
Foliar oils are another name for summer oils, i.e. oils that are applied when plants have leaves.
Supreme oils are highly refined and are effectively the same as summer oils.
Superior oils are highly refined and low in phytotoxic sulfur – which describes all modern horticultural oils. In other words, superior oils are equivalent to summer, foliar, supreme, and dormant oils. Oils once called superior oils are now mostly called “narrow range oils,” described below.
Narrow range oils are distilled at a narrow temperature range, between 415°F and 440°F. This term is equivalent to, and has mostly replaced, “superior oil.”
All-season oils can be applied any time of year. This is another more recent term, reflecting the reduced phytotoxicity of modern horticultural oils.
Mineral oils are petroleum-derived. In other words, most horticultural oils are mineral oils, whether or not they’re labeled that way.
Paraffin or paraffinic oils are petroleum-derived as well; this term is essentially synonymous with “mineral oil.”
Spray oils are formulated with emulsifiers so they can be mixed with water and sprayed. Virtually every horticultural oil you’ll encounter in a store is a spray oil.

Manufacturers sometimes combine these labels in a confusing way, e.g. “all-season horticultural dormant spray oil,” but don’t be put off. The long and short of all this terminology is that all modern horticultural oils are more or less the same in terms of composition and time of application.

Unripe neem tree fruit. Photo: Hayavadhan. CC BY-SA 3.0

Neem oil

Neem oil is extracted from the seeds of the neem tree, Azadirachta indica, which as the name suggests is native to India and Southeast Asia. Neem leaves and seeds are full of compounds with insecticidal and fungicidal properties, and neem products have been used for centuries as a natural insecticide.

The insecticide azadirachtin is derived from neem. However, it’s important to note that azadirachtin is removed by the process for refining and clarifying neem oil. Azadirachtin can be bought separately, as a water-soluble powder. So neem oil works pretty much just like a petroleum-based horticultural oil, i.e. by suffocating and dehydrating its targets and disrupting processes like feeding and mating.

How to use horticultural oils

Horticultural oils are most effective when used against susceptible insects, mites, and diseases. Identifying pests and diseases is another key IPM principle: check your plants often, identify problems, and treat before they become serious. Examples of susceptible pests, from the Colorado State University Extension:

Powdery mildew (right) on a cucumber leaf. Image: David Langston, University of Georgia. CC BY-NC 3.0 US

Aphids, overwintering mites and lepidopteran eggs, and certain scale insects can be controlled by spraying in late winter/early spring, i.e. the dormant season.
Summer or foliar sprays can control aphids, scale insects, eriophyid and spider mites, whiteflies, and leafhoppers.
Powdery mildew, discussed in this article by Piedmont Master Gardener Ralph Morini and shown in the photo at right, is the fungal disease most commonly treated by horticultural oils.

Read the label to check what pests and diseases are controlled by a particular product. The label will also tell you when to spray specific targets, and, as discussed below, how to dilute concentrated oils. Also be sure to use personal protective equipment: hat, eye protection, rubber or nitrile gloves, long sleeves and pants, and closed-toe shoes.

A hand-pumped sprayer can reach quite high into trees for, e.g., spotted lanternflies. Photo: Chris Stroupe, CC BY-NC-SA 4.0

Thoroughly cover plants when spraying horticultural oils. This is critical because horticultural oils must completely cover their targets to be effective. Spray both sides of leaves, and spray into the junctions between leaves and stems where pests can hide.

Thorough coverage means that you’re likely to use relatively large amounts of horticultural oils. To reduce cost, I’d recommend buying concentrated oils and diluting them with water in a sprayer.

Another advantage of concentrates is that you can choose the dilution to fit the circumstances. For example, let’s say you’re spraying a scale insect infestation on a chilly day in early spring. Low temperatures mean the oil’s viscosity will be high, and it’ll be less likely to flow into and clog the insects’ breathing apparatus. You should use a more concentrated oil mixture – say 3%, or about half a cup of oil in a gallon of water. On the other hand, if you’re battling a summer aphid infestation, 1% oil – or about 2.5 Tbs in a gallon – will be sufficient. The product label will tell you what dilution to use against specific pests and diseases.

Precautions

Avoid harming pollinators and other beneficial insects with horticultural oils. Don’t spray when plants are flowering, for example. If you do spray a flowering plant, do it in the evening when bees and other pollinators are less active. Horticultural oils’ low residual activity makes it easy to avoid harming beneficial insects, by simply not spraying at times when contact with oils might be harmful. As with any pesticide, don’t let the spray drift onto sensitive plants (see below) or beneficial insects.

There are a few other times when you shouldn’t apply horticultural oils. In particular, don’t use oils in very hot weather, when even modern, highly refined horticultural oils can harm plants. The damage is caused by water stress, not phytotoxic impurities: oils disrupt the plants’ waxy cuticle and exacerbate the desiccation caused by the heat. Also avoid using oils during the first few weeks of cold weather in the fall, while plants are hardening off. The reason is the same: cuticle disruption and desiccation, which can harm the buds for the next year’s growth.

Finally, some plants are particularly sensitive to horticultural oils and shouldn’t be sprayed even in moderate weather. According to CSU, don’t use oils on black walnut, hickories, spruce, junipers/cedars, Douglas fir, maples (particularly Japanese and red maples), redbuds, smoke tree, and Cryptomeria (Japanese cedar).

Concluding thoughts: are horticultural oils organic?

When used properly, some petroleum-based horticultural oils can be organic. Narrow range oils, which I defined above, are listed by the Organic Materials Research Institute (OMRI) and the US National Organic Program (NOP) as permitted insecticides and miticides. However, narrow range oils can only be used organically if the grower has already used preventative practices like crop rotation and sanitation to reduce pests. The same goes for neem oil: it’s considered organic if used with the appropriate preventative actions.

References and further reading

Horticultural Oils (PDF) Cornell University Cooperative Extension Nassau County
Horticultural oils University of Connecticut Home and Garden Education Center
Horticultural oils – What a gardener needs to know University of Nevada Reno Extension
Insect control: Horticultural oils Colorado State Extension
Pesticide profile: Horticultural oils University of Maryland Extension
Spider mites Utah Plant Pest Diagnostic Lab
What should neem be used for on plants? University of New Hampshire Extension
Use of horticultural oils in agriculture and beyond: back to the future Georgia V. Baliota and Christos G. Athanassiou, University of Thessaly

Invasives Watch

Cathy Caldwell — Fri, 01 May 2026 14:48:22 +0000

If we’ve had a recent rain — and wouldn’t that be wonderful? — the soil may be moist enough to hand-pull small, young sprouts of invasive plants. Be sure to remove all parts of the root so that the plant cannot regrow. Keep an eye out for the following invaders when you’re weeding your garden: English ivy (Hedera helix), climbing euonymus (Euonymus fortunei), Japanese honeysuckle (Lonicera japonica), Oriental bittersweet (Celastrus orbiculatus), Japanese barberry (Berberis thunbergia), autumn olive (Elaeagnus umbellata), wineberry (Rubus phoenicolasius), and garlic mustard (Alliaria petiolata).

Young small Japanese barberries are relatively easy to hand-pull, as I’ve only recently discovered. Just be sure your hands are well-protected from the sharp spines! You may even be able to pull a larger barberry if you use a hoe or mattock. It’s essential to remove all the roots. Surprisingly, the cut-stump method works on this invasive year-round, so it’s one avenue to try on larger shrubs at this time of year. See Penn. State Ext./Japanese Barberry.

Garlic mustard invading Penn Park. Photo: Cathy Caldwell

As we went to press, garlic mustard was starting to bloom. Pull it now before it sets seed. As explained by the experts at Penn. State Extension: “By early- to mid-summer (depending on flowering time), the flowers are gradually replaced by branched stems bearing the seed pods, called ‘siliques.‘ At first green, they become brown and brittle when ripe, a stage referred to as “seed shatter.” Penn.State Ext.

Aim to remove garlic mustard before it sets seed. If you pull a plant that is in flower, bag it. Do not mow garlic mustard when seed pods are present — which may be the case any time during May through September. Here’s how Penn. State Ext. explains these control principles:

Garlic mustard with siliques. Photo: Chris Evans, University of Illinois, Bugwood.org

“Garlic mustard has a taproot, and unlike some invasive herbaceous perennials, it does not regenerate from root fragments. Therefore, this is one of the few invasive plant species that can be controlled manually by pulling. Manual operations that completely remove shoot tissue will prevent regrowth. Ideally, plants should be pulled before siliques are developed, as studies have found that plants bearing siliques when pulled, even unripe ones, can still develop viable seed. For this reason, it is best practice to bag and remove pulled plants from the site, as even early pulling treatments probably include some plants that have, or will develop, viable seed.”

— “Garlic Mustard,” Penn. State Ext.

Several plants resemble garlic mustard — if you’ve got only the leaves to go by and no blooms. Two potential cases of mistaken identity are violets and our native Packera — either Packera obovata or Packera aurea. Packera leaves are less rounded and more elongated than garlic mustard. If you’re lucky enough to have a Packera that’s planted itself in your garden — and I’ve been so blessed twice now! — you won’t want to accidentally pull it before it sends up its beautiful yellow flowers! Violets have heart-shaped leaves but are smooth and shiny, while garlic mustard’s leaves have scalloped edges and a textured surface. See the photo on the right below.

Garlic mustard (left); violet (right). Photo courtesy of Blue Ridge PRISM/Garlic Mustard Fact Sheet.

Packera in bloom. Photo: Cathy Caldwell

Be aware that those helpful Fact Sheets produced by Blue Ridge PRISM (Partnership for Regional Invasive Species Management) are now located in two places: some are on the PRISM website while others are located at the PRISM’s new Virginia Invasive Plant ID & Control app. The term “app” is something of a misnomer because there’s no app to download; you simply navigate to the Virginia Invasive Plant ID & Control app webpage.

Featured Photo: Garlic mustard in bloom. Photo: Richard Gardner, Bugwood.org

Upcoming Events

Cathy Caldwell — Fri, 01 May 2026 14:54:53 +0000

PMG’s Spring Plant Sale

Saturday, May 2 @ 10:00 am – 2:00 pm

Albemarle Square Shopping Center, 600 Albemarle Square, Charlottesville, VA

Once again, the Piedmont Master Gardeners’ Spring Plant Sale will offer thousands of annuals, perennials, vegetables, fruit-bearing plants, trees, shrubs, herbs and houseplants, including a large assortment of native plants. In addition, shoppers can purchase gently used garden implements, yard décor, and other “Green Elephants” at our garden-themed thrift store.

⇒ Find out more

Plant Swap at James Monroe’s Highland

Saturday, May 9 @ 10:00 am – 12:00 pm

James Monroe’s Highland, 2050 James Monroe Parkway, Charlottesville, VA

Join other gardeners and plant enthusiasts for the Piedmont Master Gardeners’ Plant Swap. Whether you are a seasoned horticulturist or just starting your plant journey, our Plant Swap will give you the opportunity to expand and share your collection, meet other plant lovers, and learn new tips for successful growing.

⇒ Find Out More and Register HERE

Urban Tree Walks in Belmont Neighborhood of Charlottesville

Walk 1 — Thursday, May 7 from 9:00 to 11:00 a.m.
–Join the Tree Stewards on a walk through the oldest area in Belmont, featuring about 20 mature trees

⇒Find out more and register for the walk HERE

Walk 2 — Friday, May 8 from 9:00 to 11:00 a.m.
–Join the Tree Stewards on a walk through the oldest area in Belmont, featuring about 20 mature trees.

⇒Find out more and register for the walk HERE

Guided Walk: Hickories, Oaks, and Pines – Oh My!

Saturday, May 9 from 10:00 to 12:00 p.m.

VA Department of Forestry, 900 Natural Resources Dr., Charlottesville, VA

–Learn the characteristics that distinguish different species of hickories, oaks, and pines while meandering in the shade. Join Charlottesville Area Tree Steward Emily Ferguson as she points out clues to help you build confidence in your own tree ID skills.

⇒ Find out more and register HERE

Garden Site Tour at Botanical Garden of the Piedmont

Monday, May 11 @ 3:00 pm – 4:00 pm

950 Melbourne Road, Charlottesville, VA

— Explore the Botanical Garden of the Piedmont on a guided tour the second Monday of each month, 3:00–4:00 PM. Join your guide for a 45-65 minute walk through the site highlighting current projects, seasonal updates, and future plans.

⇒Find out more and register HERE

Garden Basics: Attracting Birds to Your Garden

Saturday, May 16 @ 2:00 pm – 4:00 pm

Trinity Episcopal Church, 1118 Preston Avenue, Charlottesville, VA

Using native plants, turn your yard into a songbird paradise. Planting a mixture of trees, shrubs and perennials can provide birds with year-round food, winter shelter and nesting areas. Water features, especially moving water, act as magnets for birds. Learn how a few simple tips, like saving leaves, can make your yard a healthier environment for birds and pollinators.

⇒ Find Out More and Register HERE