Each spring I delight in my first glimpse of dainty spring wildflowers scattered along my hiking trails. Welcome, friends.
Called spring ephemerals, these native wildflowers emerge when the sunlight hits the woodland floor before the first tree leaves unfurl.
They are called ephemerals because their beauty is fleeting. They come and go in just a few short weeks, dissolving back into the ground in late spring or early summer.
Why? They must bloom, be pollinated and set seed before the tree canopies steal their sun. But oh what a show until then.
It starts with a dusting of tiny pink-striped spring beauties (Claytonia virginica). Time rolls back as I remember the lawn of my childhood home awash in pink. Even their pollen is pink.
Spring beauty (Claytonia virginica). Photo: R. Rhodes, University of Maryland Extension (UME)
Boldly marching through the waves of more delicate wildflowers are the hefty trillium, named for their trio of pointed flowers and leaves.
I’m partial to the splotched leaves and red-brown flowers of toadshade (Trillium sessile) but there are lovely purple- and white-flowered forms.
I also am partial to these wildflowers’ poetic names: spring beauties, Dutchman’s breeches, toothwort, toadshade, and trillium.
In my own garden, I’ll smile over a sweep of bloodroot (Sanguinaria canadensis). Its white many-petaled blooms dance in the slightest breeze over large hand-like leaves.
Bloodroot (Sanguinaria canadensis). Photos: C. Carignan, UME
And don’t get me started on my mayapples (Podophyllum peltatum). Dangling a single lovely white flower, their splotched umbrella-like foliage hangs on until mid-summer.
Mayapple (Podophyllum peltatum). Photo: K. Baligush, UME
But wait. There’s more.
Virginia bluebells (Mertensia virginica) are just starting to edge the trails with a froth of blue and pink. My father’s favorite, they show pink in bud, then open fistfuls of sky blue bells.
Virginia bluebells (Mertensia virginica) are lining many local woodland trails. Photo: Joan Willoughby
All spring ephemerals grow low. Since they must withstand early spring vagaries of weather, they must be tough. Growing low protects them from fierce winds.
I encourage you to bend low for a closer look. Most ephemerals have delightful details you don’t notice from on high such as pollen held at the bunched bottoms of Dutchman’s breeches.
How can these spring ephemerals look so good so early? Most have thick rhizomes (thickened underground stems) or bulbs that hold energy stockpiled from the previous year.
Ephemerals’ enduring qualities mirror their ecological benefit. As native plants, they naturally support a healthy ecosystem and provide vital pollen and nectar to early native beneficial insects.
I hope I’ve inspired you to look for wildflowers on your walks and consider adding some to your landscape. But please don’t harvest them from the wild. Look for them at native plant sales and in seed or plant form in catalogs.
Happy wildflower hunting.
By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension.
Did you know that before European colonization and thanks to native land management, the area that is now northern Maryland was home to thousands of acres of sprawling prairie-like grasslands? It’s a pretty cool thing to imagine, right? Instead of dense urban centers, highways, farms, and patches of forest, most of Baltimore County would’ve been a nearly treeless ocean of swaying grasses and wildflowers! Instead of cars, shopping carts, and the hustle and bustle of people, you’d see majestic herds of deer and elk, a horizon dotted with flocks of birds, and the busyness of bees and butterflies. You can read more in a previous blog post about these eastern ‘Serpentine Grasslands’. Sadly, these grasslands no longer exist in the formerly massive extent they used to occupy, but several preserved remnants still endure here in Maryland to tell the tale of their former glory!
A stormy summer evening at Soldiers Delight Natural Environment Area, Baltimore Co. – one of Maryland’s Serpentine preservation areas. Photo: Justin O’Neill
What is the current status of the Maryland Serpentine Grasslands?
Many historic and contemporary human-driven environmental changes have caused these special ecosystems to dwindle to the point of concern; it is currently estimated that only 1.6% of their historic area in the region remains. This precipitous decline of eastern Serpentine Grasslands is concerning because they support many special plant species that are considered threatened or rare in Maryland. Luckily, several private and governmental organizations have taken to conserving and studying these ecosystems in Maryland and elsewhere (check out some of them here: Soldiers Delight and Lake Roland). Although eastern Serpentine grasslands have attracted considerable scientific research interest in terms of their rare and unique plant life, the animals that call these critically imperiled habitats home are virtually undocumented (with the exception of some rare butterflies and moths). Could there be special Serpentine associated species that we have yet to even notice?
Phemeranthus teretifolius, the Quill Fameflower, is one of the special plants that makes its home on the dry and rocky soils of Serpentine habitats. The flower is only open during a few short hours in the afternoon, during which it is abuzz with small solitary bees. Photo: Justin O’Neill
The mission of knowing what lives there to better protect it
To address this knowledge gap, our team at the EspíndoLab, have set out to start documenting the insects present in Maryland’s Serpentine Grasslands. Our current focus is on flower-visiting insects that could act as pollinators, specifically bees and hoverflies. Given the many rare and threatened plants documented in these areas, we figured it was important to first know what insects might be helping most with Serpentine plant reproduction.
How do we do this?
To document these flower-visiting insects, the lab crew has undertaken 5 years (2019 – 2023) of observations and insect collection in three of Maryland’s most intact Serpentine Grassland conservation areas. Because different flowers bloom during different parts of the growing season (spring to fall), we had to visit these conservation areas many times each year to observe the full range of flowering plants and their insect visitors. So, once every two to three weeks across each season, the Serpentine squad would head out to visit our many field study sites and systematically capture bees and hoverflies seen interacting with flowers. Currently, we are working on the meticulous process of examining each captured specimen with a microscope to determine its species identity using taxonomic guides.
Nets at the ready! The Serpentine squad carefully captures bees and hoverflies seen visiting flowers at several study sites across three of Maryland’s Serpentine conservation areas. Photo: Justin O’Neill
With this information we can begin to catalog the insect species that make up Serpentine pollination communities. This allows us to explore if the communities present in the Serpentines are different from those in nearby habitats and if they possess any rare or unique species. This information will also give us insight on how the plant and pollinator communities interact with one another; informing us about key species that contribute vitally to pollinator persistence or plant reproduction. Ultimately, the knowledge we gain will provide a baseline understanding about the dynamics of pollinator diversity in the grasslands and inform the organizations that conserve and restore these ecosystems.
What are we learning?
So far, the EspíndoLab’s efforts in the grasslands have revealed quite a bit about the broad array of insects that visit these unique plant communities. Notably, among the myriad of beetles, butterflies, flies, and wasps that visit Serpentine flowers, native solitary bees and hoverflies are consistently observed to be the most abundant – and perhaps most important potential pollinators. Interestingly, social bee species, particularly honey bees, that are commonly observed in many pollination communities, were infrequently encountered in our collecting efforts until late in the season, if it all. This suggests that they may pass on the relatively sparse floral resources of the grasslands until the Fall, when dense and attractive patches of goldenrod and aster bloom – potentially providing them an important source of resources as pickings become slim late in the season.
Most excitingly, our collections have revealed 39 unique genera of bees and hoverflies in the grasslands, so far – with more likely to be found as we continue to identify the many insects from our collections. Our efforts have also found several rare bee and hoverfly species; some of which are insects that have never been observed in Baltimore County! Among these rare and interesting finds are two bees and a hoverfly that are particularly special.
The hoverfly, Trichopsomyia litoralis, is relatively new to science – having only been described in 2019. Not much is known about the ecology of this species, but its larvae are known to feed on economically important pests. Encountering this species in the Serpentine grasslands is interesting not only because it is rarely observed, but also because it is currently thought to only inhabit an eastern coastal range (likely associated with sandy sites)! This information could extend our understanding of this hoverfly’s distribution or suggest that these flies undertake long migrations during their life cycle.
On the other hand, we have found two rare bee species that are really cool: the mining bee, Andrena gardineri; and the nomad bee Nomada seneciophila. These bees are what we call specialists: they have very specific ecological requirements. For example, A. gardineri is known to preferentially forage for pollen on plants from the genus Packera (ragworts or groundsels) – it is considered a Packera specialist. Even though A. gardineri is quite rare in the region, we find it commonly during our spring grassland collections. This is because almost all the conserved grassland areas provide good conditions to host lots of Packera anonyma.
A close-up shot of a fluffy male Andrena gardineri specimen. Photo: USGS Bee Monitoring Lab / Brooke Alexander. CC 2.0
The other notable bee we observed, the nomad bee, Nomada seneciophila is a vanishingly rare cuckoo bee (see here what these bees do and why this is fascinating). These bees wander (nomadically so) around in search of other bee’s nests so they can hijack them for their own young to develop in! N. seneciophila, as it turns out, is a specialist of our specialist friend, A. gardineri. That is, this nomad bee species has a very strong preference for stealing the nests of our other rare bee, A. gardineri!
The waspy-looking Nomad bee: Nomada seneciophila. Photo: Justin O’Neill
From these interesting encounters, it is becoming increasingly clear that these grasslands not only support remarkable plants; they also provide critical resources and nesting habitat for rare bee and hoverfly species. Although these once expansive ecosystems might not exist on the grand scale they once did, their remnants are unique contributors to the region’s biodiversity. Taking the time to document their floristic and faunistic wonders is important for understanding the historic role they played in shaping regional biodiversity today, and how that biodiversity may respond to the changing environments of the future!
By Justin O’Neill, Ph.D. student, and Dr. Anahí Espíndola, Assistant Professor, EspíndoLab, Department of Entomology, University of Maryland, College Park.
Incised fumewort (Corydalis incisa). Photo: Miri Talabac, University of Maryland Extension
Have you seen incised fumewort (Corydalis incisa)? This frilly, little wildflower is surprisingly invasive. Originally from East Asia, this species has been spreading southward along the I-95 corridor from New York since 2005. The first iNaturalist observations of incised fumewort in Maryland were made in the spring of 2018. As of this writing, Maryland contains 259 Research Grade observations. Many gardeners report that the seeds must have been present in potted plants or mulch that they purchased. In our parks, incised fumewort quickly outcompetes native spring wildflowers, and particularly dramatic declines in Virginia bluebells have been observed in the Bull Run floodplain (Northern Virginia).
Incised fumewort came into bloom in mid-March this year and normally continues blooming until early April. Seeds ripen within three weeks of blooming. Ripe seeds are explosively dispersed up to 10 feet away from their parent plants. They may also be dispersed by flowing water, tracked mud. Some reports indicate they are dispersed by ants.
Gardeners and landscape maintenance professionals tell us that manual control is unreliable at best. In some cases, even very persistent, frequent episodes of manual control have failed. Chemical control is more effective, but has its own challenges, such as unintended damage to nearby native plants.
In either case, it helps to understand that the species is biennial. The flowers of second-year plants are easy to see, but seedlings are inconspicuous. If management only targets flowering plants, that can be a viable strategy. But for folks who didn’t realize there were also seedlings present, it can be shocking to see that despite all your hard work there are even more flowering plants the next year. This gives the impression that management is failing, which may or may not be true. My casual observation is that seedlings (dicotyledons present) germinate in both spring and fall. I suppose the spring germinators go dormant for the summer and re-emerge in fall while the other seeds are germinating. The resulting rosettes are fully evergreen. The rosettes have a small, soil-colored tuber. For those of you doing manual control, make sure to remove it.
You can help by reporting this plant when you see it. You can do that quickly and easily using the iNaturalist app. Just point, click, and upload. There is even a space there where you can leave us some notes. Your observation will contribute to a publicly available map that is used by many land management agencies and their volunteers (Weed Warriors) to prevent new infestations from becoming established.
By Sara Tangren, Ph.D., Environmental Program Coordinator, National Capital PRISM, Metropolitan Washington Council of Governments. This article was published originally in the University of Maryland Extension IPM Alert, March 22, 2024.
Invasive Asian honeysuckle (Lonicera sp.). Photo: Rachel J. Rhodes, UME
Eliminating unwanted plants is often one of the most challenging chores that gardeners face. Not introducing invasive plants is the fastest and most economical way to make a positive impact, as once invasive plants are introduced to your garden, it can take many years to eliminate these invaders from your landscape.
Invasive plants propagate and spread by many different methods, which makes controlling them difficult and different for each species. Please learn feasible control tactics provided by land-grant universities or Extension factsheets/webpages before starting. Fact-based research is the absolute first step in getting ahead of plant invaders. Often invasive plants cannot be controlled 100% in just one growing season, but preventing the plant from making seeds or spreading is better than doing nothing at all.
Questions to guide your research:
Get proper plant identification! Use Ask Extension, Local Extension Professionals, and Master Gardener Plant Clinics. Smartphone plant ID apps can give you some idea, but you should follow up and confirm the correct identification. Apps may be limited by photo quality and geographic area.
Is the plant a woody perennial, herbaceous perennial, or annual?
Has the plant been a problem for several years in your landscape, or is it a relatively new concern?
You must know how it is reproducing/spreading in your particular situation. For example, if the plant reproduces from stem/root cuttings, the last action you want to take is to mow/weed-eat/till the roots, which would cause the plant to produce hundreds of new plants.
If controlling 100% is not a feasible option, determine how you can prevent the plants from spreading or allowing them to get stronger.
If you have an invasive plant in your landscape and you really enjoy it, learn how to prevent it from spreading. For example, the spread of some plants can be prevented by removing flowers/viable seeds so that wildlife does not consume and spread them, or so that wind/rain does not blow away the seeds.
Always include “MD Extension” with internet search engines to be sure that identification and control tactics specific to Maryland are being filtered to the top of your results.
Three basic control options are categorized below.
Mechanical control
Mechanical control options are often the first step that people take in controlling unwanted plants; however, these are by far the most physically demanding and often lead to a high level of site disturbance. Examples of mechanical control are:
Pulling and digging.
Suffocation or smothering with landscape fabric, mulch, cardboard, multiple layers of newspaper, anything to block the sunlight and prevent the plant from growing.
Solarization: laying plastic over the plants to “cook” live plants and viable seeds with the heat that builds up underneath.
Cutting, repeated cutting, or mowing in hopes of weakening stored nutrients so that the plants can not regenerate. This is also done to remove the flowering/seed structures.
Biological control
Biological control options utilize something else that is alive—insects, fungi, grazing livestock animals, etc. More and more of these options are being explored; however, sometimes the control agent may be 100% specific to the problem plant, or sometimes it may be able to feed on other plants too, which is the case with the Kudzu bug.
Kudzu bug (Megacopta cribraria). Photo: Russ Ottens, University of Georgia, Bugwood.org
Chemical control through herbicide application
Foliar Applications
Cut Stem or “Hack and Squirt” Treatments
Herbicides are a management tool that may be considered when other control measures have not been successful. Sometimes this control option provides the least amount of physical labor, low soil disturbance, and is more effective than other options. Pesticides can be overwhelming and intimidating, with misinformation and inaccurate “facts” being shared. If you would like to learn more about “mode of action” and how different herbicides are classified, check out this Herbicide Mode of Action link from Purdue.
A few questions that might help you determine if it’s time to explore herbicides as an option.
Have you tried mechanical or physical control options without success?
Would one application of herbicide save the soil on the site from being excavated, dug, or destroyed?
Always use the most appropriate chemical control option by finding the plant that you want to control on the product label and following the application instructions carefully.
Remember, with any pesticide (herbicide, insecticide, fungicide, rodenticide, etc.), the Label is the LAW! This is true even with organic pesticides.
The Environmental Protection Agency (EPA) is charged with approving, analyzing, and standing behind pesticides. Before approval, these herbicides are tested and labeled for use with specific instructions to minimize negative risk to yourself and the environment. Always use in accordance with the label and keep good records.
Herbicides that are commercially available to purchase have been tested to know the recommended rates and residual activity in soils and on micro/macro organisms. There are a lot of unknowns with homemade solutions, so homemade “remedies” are not recommended.
Invasive winged burning bush (Euonymus alatus). Photo: Rachel J. Rhodes, UME
Disposal of invasive plants
The last step in controlling invasive plants is proper disposal. Leftover plant materials can lead to potential accidental new infestations.
Proper disposal guidance:
Burn– If your county/city allows the burning of yard debris, be sure to follow all safety regulations and restrictions and do not breathe the smoke.
Pile– Fully dead/dried woody material that does not have seeds/fruits and is not covered in soil (which could allow it to sprout roots) can provide great nesting and shelter sites for wildlife- Read “The Value of a Pile of Sticks in Your Yard or Landscape”.
Dry or expose debris to intense heat– place debris in a black trash bag and let it “cook” for several weeks out in the hot sun, this will ensure that there are no viable seeds in the debris and all moisture is removed so that nothing can sprout. You can then add this to compost piles or dispose of it as you would “normal” landscape trimmings.
Check with your county/city government to find out if invasive plants should go in your yard waste or regular trash.
English ivy (Hedera helix)Heavenly bamboo (Nandina domestica)Yellow flag iris (Iris pseudacorus)
Let the particular plant that you are trying to control guide your management plan, and research the plant before you begin. Start control strategies on a small scale to see what works best and remember that many of the characteristics that led people to begin planting these invasives are the exact reasons that they are hard to control— some examples: wildlife resistance, good at spreading, breaking dormancy before natives early in the season. Also, keep in mind that many invasive species are a long-term fight and will require perseverance and, for best results, will require the use of different control tactics.
Lastly, once you successfully control the problem species, have a clear plan of what you will do with this space in your landscape. Installing new plants or keeping the area mulched will help prevent soil erosion or new infestations of weeds. Here is a list of recommended native plants for Maryland.
Everyone can help in the fight against invasive plants! Check the University of Maryland Extension website for an Introduction to Invasive Plants in Maryland and more information on how to reduce them. The absolute best way is to just never plant or introduce them into your landscape.
By Ashley Bodkins, Senior Agent Associate and Master Gardener Coordinator, Garrett County, Maryland. Read more posts by Ashley.
A topped tree growing water sprouts. Photo: UME-HGIC
I love trees. I’m betting you do, too. They’re striking and statuesque. They shade us and inspire us, offer wildlife habitat, and provide a backbone to our landscapes.
But sometimes bad things happen to good trees. Well-intentioned but harmful practices such as topping threaten their health.
Pruning is good for trees. Done well, it can help to control size, remove potentially hazardous branches and improve both appearance and health. But bad pruning is harmful and can kill trees.
Topping – whacking off large limbs indiscriminately to stubs – is a very bad practice indeed. It’s damaging, dangerous, and expensive.
According to Dr. Alex Shigo, the world-renowned scientist and author of books on tree care, topping is the most serious injury you can inflict on a tree.
Why do people top trees? Most have trees too big for their space and feel topping is a good way to control size and prevent hazards. It’s not. Topping weakens trees.
In fact, a topped tree is much more prone to problems, including poor health and an inclination to drop branches or fall.
Leaves are food factories for trees. Since topping removes much of the leaf-bearing crown of a tree, it literally starves it.
Topped trees react by forcing out fistfuls of thin shoots around the cut to make more leaves. Creating these shoots drains even more energy.
A stressed tree is more vulnerable to insect and disease problems. The large, open wounds topping creates invite attack.
Good pruning cuts are made where a branch meets the trunk or another branch. Trees can heal this type of cut. Topping cuts in the middle of a branch create ugly stubs that often don’t heal.
Multiple large cuts – a staple of topping – create serious wounds. The exposed wood often decays and creates a pathway for infection. Columns of decay from repeat topping make a tree more likely to fall.
The multiple thin shoots that form near a topping cut are weak and bring problems all their own. They aren’t anchored in deep tissue like a normal branch, so they tend to break.
The thick regrowth of new branches also makes a tree top-heavy and more likely to catch the wind in a storm.
Also, topping is expensive. Topped trees need to be pruned regularly due to the rapid regrowth of all those skinny branches. Repeat toppings are more costly in the long run than proper professional pruning.
Topping has hidden costs, too. Weakened trees are more likely to cause damage by falling or dropping branches. And disfigured trees do nothing to enhance property values.
According to the International Society of Arboriculture, well-maintained, healthy trees can add 10 to 20 percent to the value of your property, while topped trees reduce value.
If a tree has overgrown its space, know that there are better options, including crown reduction or removal and replacement with a smaller tree. Just be safe and leave the big jobs for the pros.
Here’s our fact sheet on tree pruning that tells you more.
Topped trees are ugly, unhealthy, hazardous, and costly. Please don’t top your trees. I want you to enjoy happy, healthy trees for a very long time.
By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension.
‘Emerald Green’ Arborvitae screening a property line. Photo: Miri Talabac, University of Maryland Extension
Q: I have limited space in a tiny city front yard and would like to block some of my view of the street. What types of evergreens would work well but not get too wide?
A: The width of the mature plants is the tricky part, since many upright evergreens mature at least 3 to 5 feet wide at their base, and not many are trimmable to keep them smaller. Plant options will depend on whether you have full sun or some shade from nearby trees or the house itself. Few city yards have issues with deer (though some do), so I’ll assume for now that browsing is not a factor.
Soil compaction is a common challenge, and poor drainage (is a roof downspout nearby?) can exacerbate root stress and cause plants to fail. If the site drains reasonably well and receives full sun in summer, your choices include slender-growing cultivars of widely-used evergreens. (Alas, there are very few native options to fit these criteria.) Examples include arborvitae (Thuja), juniper (Juniperus), yew (Taxus), Japanese plum yew (Cephalotaxus), boxwood (Buxus), and holly (Ilex).
Yew as well as broadleaf evergreens like the boxwood and holly can be pruned relatively easily to manage size, since they rebound well. Even so, it’s best to select cultivars that will mature close to the size you can accommodate without having to prune, both to save yourself the task and to reduce plant stress.
For the rest of those listed plants, especially other conifers (needled evergreens), pay close attention to expected mature size on the plant tag and make sure you have room, taking into account overhead utility lines. Take that stated size with a grain of salt too, since older plants keep growing and will not plateau at a set height forever.
Yew, Japanese plum yew, boxwood, and holly will handle a fair amount of shade and still look good, though the less sun they get, the less dense they might stay (or growth will slow). None of these species are super fast-growing (otherwise they’d get much too large for the space), but boxwoods and the upright yew varieties are among the slowest in pace. Even so, planting small, young specimens will be easier on both you and the plants (especially if shade tree roots are infiltrating the area), and they will catch up.
By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.
Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension. Our horticulturists are available to answer your questions online, year-round.
With their large diversity, bees display a huge variety of nesting preferences. Some bees that are relatively commonly encountered in our region are those that nest in stems. In today’s post, I want to tell you about who they are, their biology, and their preferences when the time comes for them to pick their nesting sites.
Who are the stem-nesting bees in our region?
When we consider bees that nest in stems, we can think about two main groups. In the first group, we have bees that actively dig into pithy stems or wood to build their galleries. In the second group, we have those that use pre-existing cavities in stems and slightly adjust them to accommodate their brood. This difference may seem trivial; at the end of the day, they will all end up in stems, right? Well, that is true to some extent; however, whether we talk about one group or the other will define what actual taxonomic group of bees we’ll be referring to, and a different set of morphological adaptations that allow them to build their nests properly.
In our region both types of bees are present and many of them are relatively common and easily observed in our green spaces.
Stem nesters that dig their nests
In addition to large carpenter bees (Xylocopa), this group includes Halictid bees such as Augochloraand the Apidae Ceratina. Because they all have to dig actively into stems to build their nests inside, all these bees are equipped with very strong mandibles, which have modifications that reinforce them, and strong muscles that allow them to increase the force they can exert on the stems.
Metallic bees are very common in our region. They often can be found emerging or looking for wooden resources to build their nests. Photo: K. Shultz (CC).
Depending on the species, we can find them building nests on different substrates. While Augochlora can often be found building galleries in rotten logs, Ceratina is mostly associated with stems that tend to be a bit hollower, such as those of raspberries and blackberries (you can check out this other post on how to trim those plants to protect their nests), or those of plants of the genus Verbena. In all these cases, the nests have the shape of a gallery, with small cells built consecutively. Each of these cells is carefully built, provisioned with nectar and pollen, populated with one egg, and finally sealed with sawdust or compacted pith.
Stem nesters that use stem cavities that already exist
Several families of bees belong to this group in the Mid-Atlantic. Species of the genus Hylaeusin the family Colletidae are present in our region, and readily nest in hollow stems. Another group that is very commonly seen in our region is that of leaf-cutter bees (Megachilidae). Although this group tends to be more flexible in the types of cavities they will use for building their nests, many species will readily use natural or artificial “stem-like” cavities (these bees are very common in bee hotels).
A small bee commonly seen in bee hotels is that of genus Hylaeus, also known as the yellow-faced bees. These bees will readily use small hollow stems and cavities. Photo: R. Cruickshank (CC).
Stem-nesting bees (Hylaeus) were observed in a raspberry cane on May 10, 2023, in Montgomery County, MD. Video: Christa Carignan, University of Maryland Extension
Because these groups do not need to actively dig into wood to build their nests, their mandibles are not as developed as those of the other group of bees I presented above. A common characteristic of all these bees is that they have relatively long and slender bodies, which is believed to allow them to move with more ease in relatively small cavities. It is also for this reason that specialists think that all these species transport pollen either internally or on the lower part of their abdomens (instead of on their legs, for example); this reduces their “width” and allows them to fit into cavities that may otherwise be too narrow. Another characteristic of this group of bees is that they often line their brood cells with special materials, such as leaves, petals, resins, or mud. This means that building these nests is a lot of work!
Leaf-cutter bees of genus Megachile are also very commonly seen in bee hotels and nesting in cavities around our homes. Here, M. centuncularis, brings leaf cuttings to line the nest in a cavity offered in a bee hotel. Photo: B. Plank (CC).
Although bees (and most insects) are generally negatively affected by urbanization, this group of bees appears to benefit from their interactions with humans. Unlike ground-nesting bees which are very negatively affected by land development and urbanization, it seems that stem-nesting bees can easily use many cavities created by humans, such as those appearing in buildings, walls, fences, and gardens.
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.
Anahí also writes an award-winning 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!
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