Insects – Maryland Grows

Meet the Smoky-winged Beetle Bandit Wasp (Cerceris fumipennis)

August 14, 2026August 13, 2026Stacy Small-Lorenz1 Comment

Closeup of fingers holding a mostly black wasp with one yellow band on its abdomen and brown transparent wings splayed. — *Smoky-winged Beetle Bandit Wasp* *Photo by: (c) hoops146, iNaturalist*,*(CC BY-NC) some rights reserved*

I was transplanting a few Blue Mistflower (Conoclinium coelestinum) plants into my drainage swale pollinator garden last weekend when I noticed this new insect visitor to my blooming Rattlesnake Masters (Eringium yuccifolium; below).

Spikey whiteish green flowers of Rattlesnake Master with a visiting Smoky-winged Beetle Bandit Wasp. — *A Smoky-winged Beetle Bandit Wasp nectars on a Rattlesnake Master flower in the author’s pollinator garden.* Photo: Stacy Small-Lorenz, UME

This gentle beauty has a name that could have been penned by a cowboy poet – Smoky-winged Beetle Bandit Wasp (Cerceris fumipennis; Family Crabronidae) – and it plays an important ecological role. It parasitizes adult metallic wood-boring beetles of the family Buprestidae, including oak-boring beetles and the Emerald Ash Borer (Agrilus planipennis), an invasive beetle that is devastating North American ash trees, especially Green and White Ashes (Fraxinus pennsylvanica and americana).

The Smoky-winged Beetle Bandit Wasp is native to Eastern North America and is the only North American wasp known to parasitize adults of Buprestid wood-boring tree pests, using the beetle bodies as hosts for their eggs and larvae. Scientists have even used this species for biosurveillance to monitor range expansion of the Emerald Ash Borer.

A combination of traits can help identify this native parasitoid wasp. Look for its black head, thorax, and abdomen and smoky-brown wings. Females may have a blue reflection to their wings. A distinctive cream or white apical band on the second abdominal segment is another key characteristic. Females have three cream-colored spots on the face, while males have two yellow triangles between their eyes.

Smoky-winged Beetle Bandit Wasp adults are active mid-June into September in the northern part of their range. They are solitary ground-nesters that generally produce two generations annually. According to Heather Holm (2021), they usually burrow into compacted sandy or gravelly soil along rivers, in paths, gravel parking lots, or even baseball diamonds, frequently near forests where they can hunt for their beetle victims in the tree canopy, then bring them back to the nest. A female captures and injects a beetle with venom, then carries it in her mandibles to stash with several other paralyzed beetles in an underground nest chamber.

The wasp carrying 2 shiny green matalic emerald ash borer beetle on a blue paper with a hole covering her nest opening. on sandy ground. There is a white golf tee holding the paper down. — A female Smoky-winged Beetle Bandit wasp brings a pair of mating Emerald Ash Borer Beetles back to her nest. The blue paper shown here will make it difficult for her to bring her victims into the nest, allowing biologists to collect the beetle bodies for pest monitoring. Photo: Philip Careless, Wikimedia Commons [CC BY-SA 3.0]

She’ll lay one egg on the top beetle that hatches after several days. She provides a larger supply of beetles for her female offspring than for the males. After hatching, her larvae will remain in their underground chambers over winter, feasting on beetles from their own personal stockpiles, before emerging as adults the following summer.

Biologists can observe the beetles that female wasps bring back to their ground burrows to document the presence of these tree pests.

These beneficial wasps are also “accidental” pollinators that pick up pollen on their bodies and transport it to other flowers while nectaring. They are harmless to humans and defenders of our forests, so two things we can do for them in return are protecting their nest burrows when we find them and providing some of their preferred nectar plants in a sunny spot near the forest, like rattlesnake master, swamp or butterfly milkweed (Asclepias incarnata or tuberosa), Virginia mountain mint (Pycanthemum viginianum), daisy fleabane (Erigeron strigosus) and Canada goldenrod (Solidago canadensis). These are relatively simple pest management practices for forest conservation that will also benefit many other pollinators.

While one species of wasp alone may not entirely solve the widespread dilemma of invasive wood-boring tree pests, there are other introduced and native parasitoid wasp species and woodpeckers that target earlier stages of the Emerald Ash Borer life cycle (egg and larval) (Shrewsbury 2026). Therefore, working in combination with other species, they could make a real difference for the next forest generation and therefore deserve our conservation attention.

By Stacy Small-Lorenz, UME Residential Landscape Ecology Specialist

This article was originally published in the UME IPM Weekly Report on August 7, 2026

References:

Holm, H. 2021. Wasps: Their Biology, Diversity, and Role as Beneficial Insects and Pollinators of Native Plants. Pollination Press LLC. Minnesota, USA. 420 pp.

Shrewsbury, P. 2026. The Exciting Life of Parasitoids and Their Role as Biological Control Agents. Presented at the Stanton A. Gill Symposium: A Focus on Biological Control. August 5, 2026. University of Maryland Extension, Clarksville, MD.

Giving Up On Plants; or, When to Commit Plant Murder

August 7, 2026August 6, 2026Erica1 Comment

I think we’ve all been there. Everything else in the vegetable garden is going well, growing as it should, producing bountifully, getting the better of challenges. And then there’s the one plant that just… isn’t. (Or more than one that just aren’t.) Maybe, though, given a little more time, a little more fertilizer, a little more effort, a little more love… it might pull through? Or is it taking up space for no reason? Worse, is keeping it around bad for your more successful plants?

When, in fact, is it the right time to commit plant murder?

I can’t help joking, but of course we all hate killing plants that we’ve tried hard to nurture, maybe even growing them from a tiny seed. But let’s face it, there’s only so much space in a garden, and the season will be over soon. We don’t want to waste the time and square feet that we have. Most of the plants in an edible garden are annuals, and with these we need to make decisions soon. With perennials, maybe you can wait until next year to see if conditions improve.

How do you figure out when and if you should pull a plant out of the garden? Well, it’s like a detective story in reverse; first, you need to be an investigator, and then a potential killer. Find out what’s wrong with the plant; assess how bad the problem is and what the consequences might be; and then make a decision based on the facts.

The HGIC website is a good place to start. If the plant in question is a vegetable, I suggest starting with the Vegetables Grown in Maryland page, select your vegetable, and visit the “Growing ___ in a Home Garden” article. From there, you can explore the list of potential problems. If you can’t figure it out from there, or from more searching online, you can contact the Ask Extension team, or ask your county’s Master Gardeners.

The problems you might encounter with plants include:

PESTS

Pest problems are often fixable. Follow the advice given at HGIC or on other regional Extension websites, and you are likely to be able to control the pests sufficiently to get a crop. However, there are a few instances where giving up on the plant is a better option.

The pest has killed the plant or come close to killing it. For example, squash vine borer can take out a squash plant in days, and if you don’t remove the pest in time, or it has destroyed most of the main stem, you will not be able to revive the plant. Flea beetles can eat most of the foliage of young eggplants, to the point where they can’t survive. But don’t jump to the conclusion that a few holes mean a devastating invasion.
The pests keep coming back even when you remove them. This happens often in community garden situations or when you have close neighbors growing the same plants. Maybe you can work together to get rid of the pests, but if that’s not an option, you might consider switching to a less susceptible crop.
There is a solution, but you can’t implement it right now. This is particularly true of animal pests—maybe you need to fix a fence or fill a hole, and it’s best done in the off-season. Or you have overplanted a bed, making it difficult to reach plants to remove pests. The easiest fix may be to remove the temptation and limit the pest’s options in the process.

A leaf of a squash plant with holes and yellowing from squash bug feeding. — *Squash bug damage in plants I couldn’t get to because I overplanted my small garden.* Photo by Erica Smith

Remember that not dealing with insect pests as soon as possible means that they are able to complete their life cycle and make more pests! If you do remove a plant that is infested, try putting it in a black plastic trash bag and leaving it out in the sun until the pests are dead. That way, you haven’t just chased them off to attack another plant. You can then put the bag in the trash or even add the contents to your compost if the plant isn’t also diseased. Speaking of which…

DISEASES

If you suspect a plant disease, diagnose it and read up on its prognosis. Does it kill a plant fast, or is it slow-working? How lethal is it and how fast does it spread? Again, it’s likely you can keep plants going for a while, for example with a common fungal disease like early blight on tomatoes, but there are cases where plant removal is advisable. If you do pull plants, put them in the trash rather than adding the debris to your compost.

Diseases that spread quickly. If you see the disease spreading to other plants, and it can’t be stopped by removing affected foliage and other plant parts, you may need to pull the plants that are diseased. This is especially true in truly destructive diseases like late blight (luckily, this is uncommon in Maryland!), but also with more common issues like bacterial leaf spot, which has devastated some of my recent pepper crops. Remember, most diseases are specific to particular species or families, so you don’t need to pull out your whole garden because one type of plant is affected.
Diseases that will prevent a plant from producing. Examples include bacterial wilt that kills a cucumber overnight (easy call), or mosaic virus that lets a squash plant continue to grow but will kill it before it has any viable fruit (harder to make the decision to pull). In perennial plants such as fruit trees, you may lose a crop one year but not the next; on the other hand, if the disease comes back for several years running despite treatment, why are you still trying? (It took me a couple years of fire blight on quince to decide I wasn’t meant to grow it.)
Multiple factors, including disease. A disease alone might not be enough to make you decide to pull a plant, but if it’s also battling pests or drought, or producing very little for some other reason, it might not be worth keeping.

A red bell pepper with rotten spots on the skin. — *This pepper damage was likely caused by bacterial leaf spot. Not worth keeping the plants going if the result looks like this!* Photo by Erica Smith

OTHER

Failure to thrive. This is a generic term for “just not cutting it”: looking puny and sad. Maybe the seed you grew this plant from was the worst one in the packet; maybe it got stressed from being in a pot too long; maybe the soil conditions in that particular spot are poor; maybe we’ve had crazy weather and the plant just can’t cope. Some TLC and fertilizer may help, but not always.
Bolting. Cool-weather crops often last into the summer, but there’s always a point when they want to go to flower, and no amount of pruning will stop it.
Failure to produce correctly. Maybe the plant looks healthy but it isn’t making what it’s supposed to make. Root vegetables that don’t make roots; beans that don’t bean; broccoli that won’t head up. A little extra time and some fertilizer may help, but possibly not. Pull the plant; do a soil test and plan an appropriate fertilizer regimen next year; look at conditions generally (enough sun? enough water?).
Need the space for something else. In a small garden, we sometimes have to make choices about what hangs in there and what gets ousted. If you want to grow kale and there is nowhere else to put it but where the tomato plant is covered with early blight and producing many fewer fruits, it may be time for the tomato plant to go.

A weak looking pepper plant with only 1 small fruit starting to grow. — This fish pepper has been looking sad all season. Might be a soil issue, or stress due to root crowding in the pot. Or something else. I still don’t want to pull it out, so I gave it some fertilizer and a pep talk. Photo by Erica Smith

In general, remember that failures are a learning experience! Sometimes we learn about a fundamental flaw in our garden or in our practice; sometimes we learn that a particular plant isn’t for us (but give it another try first!); sometimes we can just chalk up failure to a bad year or one fixable mistake. Pulling a plant is also an opportunity to put another plant in its place. (Probably not one of the same species, because the problem may affect it too.) Succession planting is made easier by thoughtful but relatively quick decision-making; get out that sick squash and you may still have time to put some bush beans in, or to get the space ready for fall planting.

And as gardeners, we always continue to hope things will be better next time!

By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.

Why don’t I see pollinators on my plants?

July 17, 2026Maryland GrowsLeave a comment

One of the most widespread actions implemented to support pollinators and other beneficial organisms is the planting of (native) flowering plants. The idea is that if we offer food to pollinators, they will come. However, we may have planted the plants, but the pollinators still aren’t coming. What could be happening? In this post, I will cover some biological reasons why this may be happening, and some solutions to consider.

Not all flowers are made equal

To a pollinator’s eye, not all flowers are the same. As we mentioned in other posts, each pollinator group (e.g., butterflies, birds, bees, flies…) has a different shape and different sensorial and physical abilities. While a butterfly may be able to reach the nectar at the bottom of a very tubular and long flower, a fly may not. Likewise, a large pollinator that is physically stronger than a small pollinator may be able to enter a very closed flower. Further, a night pollinator can obtain nectar from plants that offer it at night, while it will not get anything from those that offer it during the day…. I guess you see my point. Essentially, pollinators prefer flowers that make it easiest to locate and harvest resources like nectar and pollen. These differences mean that unless those flowers are present in a landscape, certain groups of pollinators may not be seen at all.

A grid of 9 flowers in various shapes and colors and different pollinators from bees and wasps, to moths and birds. — *Different floral shapes and colors make floral rewards more easily accessible to different pollinators. Photos: J. of Pollination Ecology.*

Not all flowers necessarily offer what a pollinator is after

Pollinators visit flowers to obtain something they need. That something may be food (e.g., nectar, pollen, parts of the flower), materials for reproduction (e.g., perfumes), materials for nest building (e.g., resins, floral oils), or simply a place to overnight, stay warm, and/or mate. As a matter of fact, not every single flower serves all those needs, making the pollinators end up “sorting themselves” among the plants that offer what they need.

A yellow blooming flower cluster with a bee climbing inside one of the blooms. — *A bee of the genus Chalepogenus visiting a flower of Calceolaria dentata (native to Chile and Argentina) to collect floral oils and pollen. Photo: A. Espíndola.*

Let me give you an example. In my research life, I work on a specialized pollination system that involves flowers that do not offer nectar at all, but instead offer floral oils (and pollen) in exchange for pollination (you can read more about this from the blog post: Why Do Pollinators Visit Flowers?, May ’20). These flowers are called lady slippers and belong to the Pan-American genus Calceolaria. When we observe which pollinators visit the flowers, we see that it is mostly bees who specialize in collecting floral oils (in our case, bees of the genera Centris and Chalepogenus), and basically nothing else. In landscaping, filling our yards with only one specialized flower type drastically limits pollinator diversity. For instance, if we only planted oil-producing flowers, we would not see many diverse pollinators. This highlights a key rule: the rewards a plant offers dictate the visitors it attracts. Just as varied flower shapes are crucial, providing a diverse mix of nutritional rewards—like nectar, pollen, and oils—is the best way to boost the number and variety of pollinators in our green spaces. As for the floral shape I was referring to, planting species that offer different types of rewards is a very good way to increase the number and types of pollinators we see in our green spaces.

The flowers do not necessarily want to share too much

Plants attract pollinators because they can get pollination from them, which allows the plant to reproduce. From a biological point of view, a pollinator will be a good one if it carries pollen from the stamens of a flower and makes it land on the stigma, so it can germinate and then fertilize the ovules. This is all good and nice; the problem, however, is that many pollinators use pollen as food. This creates a conflict between the plant’s and the pollinator’s interests: a plant needs the pollen (that contains its sperm) to not be eaten but to fertilize its ovules, but many pollinators just want to eat the pollen (and they have good reason for this, since a pollen grain is extremely rich in nutrients!).

A black and white microscope image of pollen grains. Some are spikey, some round, and some beanshaped with cantelope rind-looking texture. — *Pollen grains have different structures and shapes. Photo: Dartmouth College Electron Microscope Facility.*

As a response to this conflict, some strategies have evolved that somewhat “control” the feeding on pollen that pollinators may do. In fact, plants protect their pollen with physical structures that make it hard to be broken by pollinators. Some of these pollen grains feature spikes and thickened walls, which force pollinators to use specialized tools to break through them. Along with this physical “shield”, pollen grains often contain what are called **secondary metabolites.** These are chemical compounds that make the pollen indigestible or toxic, unless the organism trying to eat it has evolved ways to tolerate those compounds themselves. Closely related plants produce similar chemical compounds; the unique chemistry of a plant family dictates which pollinators can digest its pollen. This leads to different levels of floral specialization on the side of the pollinators. Pollinators will only try to visit plants that offer pollen they can digest, which again, restricts the flowers they visit. As for the previous points, increasing the different types of plants by having representatives of different plant families can increase the variety in the chemical quality of the pollen offered, attracting and supporting different types of more or less specialized pollinators.

By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.

Small but mighty. The amazing ground-nesting bee!

June 19, 2026Maryland GrowsLeave a comment

The summer is almost here, and if you are like me, you have already been outside and seen a bunch of tiny bees digging, digging, digging, and buzzing around flowers. Who are these little ladies? And what on earth (pun intended) are they doing? In today’s blog, I want to explain a bit about these super powerhouses, how they do what they do, and point to some of these cool bees that we can find right here in Maryland and our general region.

What are ground-nesting bees?

As its name indicates, ground-nesting bees are bees that nest in the ground, mostly by digging their nests. Ground-nesting bees are found in several families of bees, and being a soil nester/digger is actually one of the most common nesting strategies among solitary bees. In these bees, once the female finds a good nesting site, she starts excavating it to create an underground nest, which often has several brood cells, in which the larvae develop. These nests are usually found in spaces where the vegetation is sparse or the soil bare, and can sometimes be built along with other nests of the same species, leading to communal nesting areas. It is because of this preference for relatively open ground that it is often recommended that at least some uncovered ground is left in our green spaces, which helps provide habitat for their establishment.

A tiny bee is seen crawling out of a mound of soil on the ground. — *Ground-nesting bee coming out of her nest. Photo: Colleen (CC0).*

How do ground nesters build their nests?

As good miners or soil diggers, ground-nesting bees also have specific behavioral and morphological traits that make them good at what they do. Bees that excavate have modified leg structures that allow them to easily move within tunnels, strong mandibles that they use to actually dig the cavity, and modified extremities of the abdomen (the pygidial plate) that function as sorts of trowels and allow them to pack soil on the walls of the cavity they are digging.

Along with having the right tools of the trade, these bees are also selective of the type of soil they use to build their nests. Most ground-nesting bees prefer soils that are not too compacted, with at least some sand content, which makes them easier to dig through. This means that it is more likely that we will find these bees in rockier/sandier soils than in super clay-y ones. As a matter of fact, many ground-nesting bees are associated with dune nesting, and because dunes are often endangered habitats (because they are often disturbed/destroyed by human activities), many sand-nesting specialists end up becoming endangered as well. And as a fun fact about soil choice, bee experts think that because finding “good soil” is so important for the survival of these bees, bees tend to become associated with specific spots for nesting, with the nesting site becoming a sort of “family place”, where several generations of females from the same family line come back to nest over the years/generations.

A close up of the pygidial plant which is a small darker triangular structure at the tip of the bee's abdomen. — *The pygidial plate is a structure present at the tip of the abdomen of ground-nesting bees that functions as a trowel. Photo: MN Native Bees.*

Because digging through the soil with their mandibles (and sometimes their legs) is hard work, bees usually tend to choose the best timing to start their digging. In fact, the hardest part of the soil to dig through for a bee is the surface, which is often the most compacted. For this reason, bees tend to start digging after the soil has become moist (e.g., after rains). Incredibly, some ground-digging bees are even able to add, if needed, secretions or even nectar to humidify and loosen the soil! Once the bee has started her excavation, she continues digging deeper and bringing soil out of the construction area, which leads to all sorts of “mounts” being built around the nest entrance and sometimes chimney-looking structures.

What are some ground nesters from Maryland?

Andrena vicina – The neighborly mining bee

a close up of a bee gathering pollen from white flowers — *Andrena vicina.* *Photo: K. P. McFarland (CC0).*

This Andreniid is relatively large (about 1- 1.5 cm), present in North America and common in the Eastern USA. This species received that cute name because it is one of those that builds communal nesting areas (“neighborhoods”). In Maryland, the species is active right now (~June/July) and is generally seen visiting many native plants and crops. In particular, this is one of the known visitors of, among other plants, Rhododendron and Azaleas, several heather family plants (like Vaccinium, Kalmia), as well as several rose family plants (Prunus, Rubus).

Augochlorella aurata – Golden sweat bee

a tiny metallic green sweat beed in the center of a yellow flower

Augochlorella aurata. Photo: C. Martin (CC0).

This is a species in the Halictid family, and is called a sweat bee because it is often found collecting sweat (for water and salts). This is one of those tiny bees that you may find landing on you on a hot day, really committed to not letting go of your skin! This particular bee is relatively easy to recognize because it is small, metallic-looking, with beautiful green/golden iridescence. This bee is not fully solitary and is a species recognized to display primitive eusociality (for example, honey bees are true eusocials). In this species, there is a queen that starts a nest, and across the season, generations of first infertile and later fertile workers are produced. By the end of the season, the fertile workers are inseminated and disperse to overwinter. This bee species is pretty generalist in its choice of plants, known as a pollinator of many crops (e.g., apples, tomatoes, watermelon) as well as native plants.

By Anahí Espíndola, Associate Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.

Anahí also writes an Extension Blog in Spanish! Check it out here, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Enhance Biodiversity in Your Vegetable Garden by Planting More Flowers!

May 28, 2026Maryland GrowsLeave a comment

A view of a fenced in vegetable garden with Salad tables in the forground and multiple raised garden beds full of various vegetables. Bright orange marigold flowers line the edges of the raised beds and there are wood chip paths inbetween the planting areas. — *Marigolds line the edges of raised garden beds, bursting with vegetables in this county extension demonstration garden. Photo: Jon Traunfeld*

A practice generally used in agricultural contexts is that of floral supplementation. In today’s blog, I would like to dig a bit into this idea and present some strategies to implement it at smaller scales, like small vegetable gardens and green spaces. Read along to learn a bit more!

What is floral supplementation?

Agriculture using western methods generally leads to losses of plant biodiversity in and around fields, mostly because it transforms diverse spaces into large monocultures (the crop fields). This, in turn, reduces the ability of the ecosystem to regulate pests, maintain pollination and eventually can negatively affect yield and production, along with increasing environmental erosion. As a response to these needs, strategies have been developed to increase biodiversity in agricultural contexts, and one of those is floral supplementation. In this strategy, the areas surrounding the crop fields are planted with diverse floral mixes or hedges, or the crop rows are intercropped with flowering plants. Such approaches improve soil quality and reduce erosion, increase diversity of plants and animals associated with them, and in many cases lead to improved pest control and pollination of the crop. Although this is a practice more or less widespread and recognized for production fields, it is not often officially promoted in smaller areas such as gardens or the green spaces that surround them. Let’s fix that! 😊

Why does floral supplementation work?

The idea behind these practices is that they increase the spatial and plant resources available to the local biotic community. By increasing the number of plant species present in an area, the different types of food and nesting resources are also increased and become more complex. For example, there may be flowers that bloom at different times of the season, that produce different types of nectar and can support different pollinators, fruits that support different insects and birds, plants of different heights and structure that can offer shelter to different organisms. These modifications eventually lead to more diverse animal communities being present in the area where the supplements are added. From the point of view of the benefits of these changes on the actual performance of the crop field, this diversity promotes the presence of biological control of pest agents (e.g., predators of pests, parasitoids), as well as increases the diversity and abundance of potential pollinating species. The presence of a more robust plant community can also promote soil retention through the presence of more roots to physically retain it, reducing erosion and water runoff.

Tomato plants with green tomatoes growing in a raised garden bed with a railing in the background. Interspersed plantings include basil, and chard. — *A way to implement floral supplementation in small spaces is through the combination of different crops on the same pace, such as offered by the idea of companion plantings. Photo: Steph L.*

Floral supplementation in gardens

Although the extent of floral supplementation done at the agricultural scale can not be reproduced at the garden level, the same principles can be implemented, especially if the gardening space is not necessarily embedded in a very biodiverse context. Here are some ideas on how to do it.

Intercropping and Companion Planting

A cool way to both increase diversity and production per unit of area is the use of intercropping with companion plantings. Here, different crops can be interplanted, with rows alternating species, or with several crop species planted in a mixed way in the same part of the garden. This relates to the idea of companion planting, where species that are planted together are selected for their ability to successfully coexist and support each other. The table gives some ideas on potential combinations to promote and avoid.

Companion planting promotes the interplanting of different crops/herbs, with species known to be compatible and incompatible in these plantings. Table from Virginia Cooperative Extension publication, Companion Planting in Gardening

Hedgerows

Green bushes with pink flowers along a grassy area under trees. — *Especially if planted with native species, hedgerows can offer a complex structure for a lot of animal diversity to establish close to our gardens. Photo: M. Gimber.*

This strategy can be especially effective if there is a lot of room around the garden plot. Instead of leaving that as a mowed space, it is possible to turn it into a structurally and species-diverse space! For this, one can consider planting sets of native shrubs/small trees that can provide complex shelter spaces and flower/fruit/seed resources for many animals (including humans! 😛 ). Some choices I really like for our area are fringe trees, spicebushes, witch hazels, hazels, pawpaws, serviceberries, native elderberries, or redbuds. Of course, not all these species are appropriate for all areas, so depending on the level of light and soil conditions, some may be preferred over others.

Flower Strips

A close up of Monarda or beebalm with red blooms — Even when not much space is available, the planting of native herbaceous plants can lead to an important bump in diversity around our vegetable gardens. This strip of *Monarda, Solidago, Penstemon, Rudbecia* and some other native plants is directly adjacent to my vegetable garden and attracts many pollinators and predators such as wasps and mantids. Photo: A. Espindola.

Flower strips are also a great choice, and if space is available, one can easily turn them into a small floral meadow. These spaces can be planted with seed mixes, which can be purchased from seed companies specialized in the establishment of native meadows. (Be sure to review the species list since some meadow mixes can contain invasive or borderline invasive plants, others may contain annuals like Cosmos.) If the space available is not very large, it may be more practical to just plant a set of native flowers that bloom at different times through the season. Check out this other post where I direct people to some specific plant lists that can be handy for our area. Especially if the species chosen are perennial, the planting will lead to a long term establishment, and if wanted, new plants can be added over the years, as some species become more established.

Book Review: The Nature of Oaks

January 15, 2025January 15, 2025Maryland GrowsLeave a comment

Winter’s leafless landscapes, while beautiful in their own right, can look barren compared to the cacophony of color and activity of late spring/early summer. Once an oak’s leaves have senesced and its acorns have fallen, you’d think that not much is happening way up there in the canopy. But surprisingly there is! Tallamy’s The Nature of Oaks, takes the reader on a month by month journey of how these mighty trees support an abundance of life year round.

In fact, indigenous oaks (genus Quercus) support the highest number of Lepidoptera (butterflies, moths, and skippers) species in the mid-Atlantic region- some 534 different native species (Tallamy & Shropshire, 2009). Lepidoptera in the larva or caterpillar stage, such as the Greater Oak Dagger Moth (Acronicta lobeliae) (Fig. 1), often have a narrow diet breadth feeding on only a single family of plants. The over 500 species of caterpillars that oaks support, in turn, feed birds and other wildlife further up the food chain.

Fig. 1. Greater Oak Dagger Moth caterpillar. Photo: Nick Furlan

Tallamy’s Nature of Oaks gives numerous examples of insects’ impressive camouflaging, and describes how it helps them go undetected by hungry birds. For instance, the oak specialist American Oak Beauty (Phaeoura quernaria) blends in amazingly well with its host plant during both its larval and adult stages (Figs. 2 & 3). It’s no wonder that we often don’t notice all of the activity on oaks, especially given that much of it takes place at night.

Photo of an American Oak Beauty caterpillar on a tree twig. The caterpillar looks very much like the tree twig. — Fig. 2. American Oak Beauty caterpillar. Photo credit: Adrian Romo

Photo of an American Oak Beauty moth on the bark of an oak tree. The bark is covered with gray and green colored lichens. The moth's body colors and color pattern make it difficult to see the outline and shape of the moth. — Fig. 3. American Oak Beauty moth. Photo credit: Basil Conlin

Tallamy also considers what’s going on beneath the canopy. Many oak-dependent species complete their life cycle in either the leaf litter or soil at the base of the tree. Research by our state entomologist and UMD alum Max Ferlauto shows that raking less results in more butterflies, moths, and beneficial arthropods. The harmful effects of leaf removal are widespread, impacting community composition, nutrient cycling, and soil stability (Fig. 4).

Illustration showing the negative effects of removing leaves from the ground. — Fig. 4. Negative effects of leaf removal. Illustration by Maggie Lin

Of course oaks support a host of other arthropods and critters- from tiny wasps that form galls on oak leaves and terminal buds to numerous birds and mammals that depend on the trees’ nutrient rich acorns. Tallamy’s Nature of Oaks contains compelling data and entertaining anecdotes that left me awestruck by the beauty and interconnectedness of these mighty trees with all living things. Tallamy suggests if you can only plant one tree, make it an oak.

If you’re feeling inspired to plant an oak in your yard, Tallamy provides guidance on where and how to plant oaks for long term success. For instance, to overcome the concern of tree damage, he suggests planting young trees closer together (vs a specimen tree) so that they’ll be smaller in diameter and their roots will interlock. In Maryland, we’ve 21 native oak species that are commercially available, including two that reach a max height of 20 feet. For photos and details on growth requirements, habitat value, etc. see the new Commercial Maryland Native Plant List.

Where can you purchase native oaks (and other plants)? This month, the MD Department of Agriculture (MDA) launched a certification program for wholesalers, growers, and retailers of native plants. The program will make it easier for consumers to find sellers via a tiered system (novice, pro, and premium). Certified sellers will be listed on MDA, MD DNR, and UME’s web sites (coming soon). The program will also help consumers quickly identify which plants are native to MD via a new ‘Best Maryland Native Plant’ logo that retailers are encouraged to use on plant tags and signage.

If you’ve any questions or comments about growing or using oaks or native plants in general, I’d love to hear from you at lkuder@umd.edu.

Reference:

Tallamy, D. W., & Shropshire, K. J. (2009). Ranking lepidopteran use of native versus introduced plants. Conservation Biology, 23(4), 941-947.

By Lisa Kuder, Native Plants and Landscapes Specialist, University of Maryland Extension. See more posts by Lisa.

Leave the Leaves, All While Not Making Your Neighbors Mad

November 13, 2024Maryland Grows4 Comments

With the fall season we are starting to see a lot of articles talking about the massive ecological and soil quality benefits of leaving leaves, stems, and sticks in our green spaces. As a biologist, I understand why doing so is indeed the right thing to do, but I often face pushback on this topic from people I mention this to through my Extension work or just in my neighborhood. There are of course many barriers to adopting such practices that I have heard people mention, but one that comes up often is the one that involves social or peer pressure. In other words, how to adopt this without making your neighbors mad? In today’s blog, I want to give some pointers to avoid conflict with (and maybe even convince) neighbors who may be less convinced than you on these practices.

Some fall practices that we know are good for biodiversity and your soil

I do not want to talk yet again in depth about these practices (you can read more about it in these other articles if you want to know more):

But I want to just quickly state some of them, so you know what I am referring to throughout this article. I feel that there are three major types of practices that can be adopted for protecting pollinators and other insects during the winter: leaving the fallen leaves on the ground, not pruning certain pithy stems to the ground until the Spring, and making branches and stick piles in sections of your green spaces.

For all these practices, common sense should be used when deciding whether to adopt them or not (e.g., if you are in a fire-prone area, perhaps making huge wood piles is not a good idea), remembering that these are indeed all practices that have been shown to improve biodiversity in our green spaces.

Fallen tree leaves have been spread about fours inches deep in a wide circle around the base of a very large tree in a backyard. Stones are used to create the circular perimeter and contain the leaves. — Piling the leaves around trees is a good way to retain them in the green space, all while giving an impression of “tidiness” to the yard. Photo: D. Mizejewski.

How to avoid “leaving the leaves” look messy?

So, you want to participate in the ”leave the leaves” action, but you still want to make clear that somebody is actually taking care of it. What to do?

If you have the option to ignore others’ opinions, you can just leave the leaves where they fell and go on with your life. 😊 That said, this may or not apply to most people.
You can pick certain areas of your green space to leave the leaves, but rake other areas. Perhaps you want to have the areas that are less exposed to people’s eyes be those selected for leaving the leaves. This will show that your leaving the leaves is purposeful and not just a lack of care.
If you have trees on your space, you can also decide to pile up the leaves around trees. This will provide shelter to insects and other small critters, provide mulch for the tree, and sign active care of your space.
A problem I sometimes hear about is leaves blowing over to another person’s yard or space. To avoid this, you can use plants to line/fence your green space. These plantings will have the positive effects of both allowing your leaves to stay on the ground, while minimizing “spill overs”.
Explain what you are doing. You can tell your neighbors about what is going on, and even put a sign up to clarify what is happening (if you want to go “fancy”, the Xerces Society has a neat one).
A thing NOT to do if you would like to retain arthropod diversity but also make the leaves look “tidier”, is mow them over. This has been shown to kill the insects that were preparing to overwinter in them. ☹

A "Pollinator Habitat" sign is visible in this part of the landscape where fallen tree leaves are spread about four inches deep in a garden bed. The sign explains that the leaves help overwintering pollinators survive the winter. — Displaying a sign that explains that some activities in our green spaces are creating pollinator habitat can go a long way. Photo: C. Corner.

How to leave the stems without issues

Another practice shown to support stem-nesting insects (including several bees) is not trimming pithy stems all the way down during the fall.

If you have the option to ignore others’ opinions, you can just leave the stems and go on with your life. 😊 That said, this may or not apply to most people.
As for the leaves, you can select sections of your space where you decide to implement this. An extension of this idea is that perhaps you can reconsider where your plantings are, so you have the pithy plants (e.g., brambles) in areas that you know are not going to be looked at all the time.
You can also decide to trim the plants down to some extent (about 2-3 ft from the ground) but not completely. This will show that you are taking care of the plants, but that you actively decided not to trim them all the way down.
Letting people know what is going on is always a good thing. You can add a little sign to tell people about what you’re doing and why, and/or you can talk to your neighbors to let them know.

2 foot to 3 foot lengths of tree branches and sticks are piled together in an out-of-the way spot in the yard to provide habitat for insects and other small critters. The pile is surrounded and held up four medium-size sticks stuck in the ground vertically at the corners of the pile. — Make your wood and stick piles look “organized” by defining spaces in your yard that you allocate to creating those biodiversity habitats. Photo: Natural History Museum.

Making a pile of sticks and wood without scaring people

Making stick piles is a very good practice to retain biodiversity in green spaces. That said, people can feel like a pile can look untidy, and even some cities may have some regulations about what type of pile may be OK versus not.

If you have the option to ignore others’ opinions, you can just make a pile and go on with your life. 😊 That said, this may or not apply to most people.
You can restrict the pile clearly to a specific area of your space, and make clear that you have actively decided to make one and are taking care of it. This is to sign that this is not just some brush you left around after you trimmed some plants, but actually a specific green space feature you are trying to build.
You can make it look cute. Check out this other blog, A Brilliant Fall Banquet, where some ideas are given.
Information, information, information. Let people know what this is and why you are doing it. And also, if there are some afraid of snakes or fires, make sure that the area you live is not known for its high fire or venomous snake danger (you can inform yourself about these topics online or ask an Extension agent; e.g., Venomous Snakes of Maryland.