How Are Aquatic Plants Pollinated?

When we think about pollination, we tend to only think about terrestrial plants. However, a large number of plants are not and actually live fully or partially in the water. These plants also need to reproduce, and thus need to have their flowers pollinated to produce seed. How do they do it? In today’s post, I will try to give a (short) answer to that question, using some native plants as examples.

You may recall from previous posts, that flowering plants require pollination to be able to produce seeds and thus reproduce. Since we are terrestrial organisms ourselves, we tend to be more aware of other organisms and processes that share that trait with us, and pollination is no exception. However, there are lots of flowering plants that are completely or partially aquatic, and these plants also require pollination to produce seeds. Depending on the specific requirements of the plants in question, some of them may use different strategies for pollination.

Wind pollination

Many aquatic or semi-aquatic plants depend on wind to transfer pollen to the female reproductive structures. Especially under conditions distant from land, using wind as a means of pollen dispersal can be extremely advantageous. In fact, being distant from land tends to reduce the types and number of animals that can visit the flowers of aquatic plants. By depending more heavily on wind, these plants usually display light and abundant pollen that can be readily blown away and potentially deposited on the stigma of the female counterparts. A global evaluation of this indicated that about a third of all aquatic plants in the world are wind-pollinated.

In Maryland, an aquatic plant known to be wind-pollinated are watershields (Brasenia schreberi). This plant has non-showy flowers that display both anthers and stigmas. In order for the plant to promote cross-pollination (i.e., avoid receiving pollen from its own flowers), the flowers of these plants go through a complex blooming process that spans two days. This process involves on the first day the receptivity of the stigma (the female part that receives the pollen) and on the second day the maturation and release of the pollen grains. When the grains mature, they are swept by the wind and can reach stigmas from other flowers that are at that point going through their first flowering maturation step.

Animal pollination

It has been shown that a large number of aquatic plants are at least partially pollinated by insects or other animals. In fact, as is also the case in terrestrial plants, aquatic plants can sometimes use both wind and animals to transfer pollen, increasing the chances of some pollen eventually reaching the stigma. Animal-pollinated aquatic plants are pollinated by a large variety of organisms, but their identity will depend on the specific place where the plant is growing and the ability of the pollinator to reach the plant and even survive in that environment. For example, while large bees may be able to fly further away from land, smaller insects may mostly visit plants that are close to land.

A special case of insect pollination of a Maryland native is that of the arrow arum or tuckahoe (Peltandra virginica). The species belongs to the Araceae family and displays a stunning pollination system. As is often the case in this family of plants (see also the skunk cabbage example we talked about in a previous post), the maturation of the female and male flowers is linked to the production of specific aromas. In the case of the arrow arum, these smells attract small flies, and in particular individuals of Elachiptera formosa. These flies seek the flowers to mate, feed on pollen, and eventually lay eggs on the plant, making this an example of what is called nursery pollination (the plant receives a pollination service in exchange for providing a brood site for the pollinator). By moving along the flower, these tiny flies move pollen from the anthers to the stigmas. Some of this pollen may come from the same plant, but other pollen may come from a different flower already visited by the flies.

Water pollination

Finally, many aquatic plants display flowers that are either completely submerged or floating on the surface of water. These plants usually use water currents to disperse their pollen. As with wind, this dispersal is very inaccurate, which usually leads to the release of a large amount of pollen. These plants have either pollen that floats on water or remains attached to the anthers which float to the stigma.

aquatic plants with tiny white flowers on the surface of water
The American pondweed is one of our native species that uses water as their means of pollen dispersal. Note the very small white flowers that are placed on the surface of water. Photo: C. Fisher

A very common native from Maryland that displays this type of pollination is the pond- or waterweed (Elodea canadensis). This species native to North America displays flowers that have either anthers or pistils, but not both. The flowers with anthers are often displayed over the water, from where they release the pollen, which lands and then travels on its surface. By moving on the surface of the water, the pollen can reach the slightly submerged stigmas of the pistilate (female) flowers, which are held on flowers that float at the very surface of the water. Because such a dispersal can lead to large pollen loss, pollen release in this species is only done when the wind is light and the water current is low. This promotes a more “controlled” dispersal and increases the chances of the pollen effectively reaching the stigmas.

By Anahí Espíndola, Assistant 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,, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

And the Pollinator Prize Goes to… Hoverflies!

We hear a lot about pollinators these days, but most of the attention appears to always go to one group of them: bees. However, the diversity of pollinators expands way beyond this one group of insects, as we discussed in a previous post. In today’s post, I want to bring the spotlight to one of those non-bee pollinators, which I always feel stay in the background of our pollinator discussions and are massively underappreciated, despite their important role in our ecosystems. Come with me to give hoverflies the recognition they deserve.

What are hoverflies?

With over 100 species in Maryland, hoverflies (sometimes also called flower flies, or simply syrphids) are a group of flies that belong to a family of insects called Syrphidae. They are called hoverflies because they are very good fliers, able to quickly change directions or maintain their flying positions in very impressive ways. While their larval stages can have a huge variety of nutritional needs (some of which make them great biological control agents of pests), a very large number of the species are strongly associated with flowers as adults. In fact, the females require nectar and pollen consumption for their ovary development, making them depend strongly on floral resources for reproduction. For this reason, they act as important pollinators of many wild plants and crops, especially in temperate climates. Although not fully recognized by the general public, pollinating hoverflies have been shown to contribute globally to the pollination of over 70% of crops globally and about the same percentage of European wildflowers (few studies have evaluated the latter in North America)! You can learn more about this in this recent publication.

Hoverflies can be recognized by their large eyes, short antennae, and at rest their wings positioned perpendicularly to their body, as seen here in this (likely calligrapher or Toxomerus) hoverfly from Maryland. Photo: A. Espíndola

Ecology and biology of hoverflies

I hope that you’re now starting to get excited about these little creatures. Before you run outside to try to catch a glimpse of them, let me tell you some more about their lives, so you can continue to be amazed at what they do and why I am on a “pollinator recognition” mission for them.

As I was saying before, a vast majority of hoverflies are strongly associated with flowers. This makes them potentially important pollinators, and this is indeed true for many of them. However, there’s another reason why they are so important: their ecology. In fact, hoverflies have migratory or at least long dispersal behavior. This means that they have great potential for long-distance dispersal of pollen, and thus can contribute strongly to the pollination of plants that may be spatially far away from each other. Thinking about pollination and its role in plant reproduction, such long-distance pollen dispersal can be key in the reproduction of isolated plant populations, and even in increasing and maintaining genetic diversity in those populations. All of that tends to positively impact the ability of those plants to maintain their populations, making hoverflies key actors in sustaining the diversity of many wild plant species.

And also, because I really want to make an impression on you 😊, know that when I talk about hoverfly migration, I am talking about migration patterns that can in some cases be equivalent to those of more “famous” insects, such as monarchs. Some studies have shown some hoverfly species migrate thousands of miles, following the seasons. Although this is relatively well-studied in Europe, we know that similar migration patterns also occur in other parts of the globe, including North America. And as a fun fact, in our research group at UMD, we believe that we once observed and sampled a wave of migration of hoverflies right here, while studying pollination interactions in the endangered serpentine grasslands of Maryland.

a fly that looks like a bee with large black eyes

a syrphid fly that looks similar to a bumblebee

a syrphid fly has yellow and black stripes and two wings
Hoverflies often trick us into thinking that they are something they are not. Here we have some great examples of elaborate mimics of bees/bumblebees and wasps. Can you spot the traits that give them away? Top: Bare-eyed bee mimic (Mallota bautias); center: Hairy-eyed bee mimic (Mallota posticata); Bottom: Transverse-banded flower fly (Eristalis transversa). Photos T. Shahan, M. Wills, J. Gallagher. All CC.

How to recognize them?

Perhaps a reason why hoverflies are underrecognized is that many of their species display impressive body mimics of other species, many of which people tend to be afraid of because of their stingers. For example, some of the most common hoverflies in our area display yellow and black stripes, tricking us (and potential predators) into believing they are in fact wasps or bees. This is a strategy that protects them from predation but also requires us to be more attentive when we are trying to find them.

Despite this, there are some simple ways to recognize their trick. Because they are flies, hoverflies have characteristics that differentiate them clearly from other groups of insects, such as wasps. One of the main traits to look for when trying to figure out if we are facing a hoverfly (vs. a wasp, for example), is looking at their wings. Unlike bees and wasps, flies have only one pair of wings, which at rest they usually extend perpendicularly to their body, which makes them look like a plane or a “T”. Wasps and bees, on the other hand, typically don’t do this, and they fold their two pairs of wings flat over their abdomen while they are at rest.

Another way to tell them apart from most other wasps and bees is their heads (this may be also useful when the wing trait is not easy to see). In fact, flies generally have VERY large eyes (just think about any fly costume 😉). Hoverflies are no exception! They also have large eyes that cover a very large part of their heads, as well as very short antennae. On the other hand, bees and wasps, usually have much much longer antennae that extend way beyond their heads.

Ready to go out and find some of them? Remember that you can always check out iNaturalist to help you out with identifications! Good luck!

By Anahí Espíndola, Assistant 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,, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

An Ode to Beebalms, Our Beautiful Biodiversity Magnets

Scarlet beebalm (Monarda didyma). Photo: A. Espíndola

Among the many native plants of North America, there’s one that every summer stuns me with its beauty and its important role in our ecosystems and our lives. In today’s post, I want to share some information about a lovely group of plants local to right here, which can be easily grown in our green spaces, and which one can observe flowering right now: beebalms!

What are beebalms?

Beebalms are a group of plants in the mint family (Lamiaceae) that belong to the genus Monarda. This genus is restricted to North America and includes several species. In Maryland, there are at least four species present, one of which (M. clinopodia, the basil beebalm) is currently listed as requiring conservation actions (listed as Vulnerable). The other three species (M. didyma, M. fistulosa, M. punctata) appear to be relatively common in the region and are easy to grow in our green spaces. All species reach about 2 to 5 feet in height and are great additions to flower beds because of their beauty but also because they act as biodiversity magnets. For example, the genus Monarda has been recognized as supporting at least three rare and specialist bee species in the Eastern USA, and attracting a lot of natural enemies of pests, meaning that providing these floral resources can support the populations of bee species that depend on the pollen of these plants for their nutrition and help us naturally control pests in our green spaces. And last but not least, later in the season their fruits support birds and, if left uncut, their stems offer overwintering spaces for arthropods.

Scarlet beebalm (M. didyma)

This is a perennial species with dark red flowers that bloom during the summer. As for all beebalms, the flower heads are formed by many elongated flowers that harbor abundant nectar. The plant is incredibly attractive to pollinators, acting as a magnet to bees of all sizes, butterflies, and hummingbirds. Besides its great support to pollinators and other arthropods, this species (along with M. fistulosa) has medicinal properties, which have been identified and used since immemorable times by Native Americans. The very name of beebalm is even related to these uses, since the plant can be used to produce poultices that help with skin affections, including bee stings. Preparations of the plant are also traditionally used to help with digestive and respiratory issues. Finally, as for many mint plants, this species is rich in essential oils, which makes it a good one to flavor foods like one would do with oregano and mint. You can learn more about how to grow this species, along with other facts on this USDA information sheet.

a stand of brightly colored red flowers - monarda didyma

Scarlet beebalms display red flower heads that offer abundant nectar to a large variety of vertebrate and invertebrate pollinators. Photos: A. Espíndola, J. Schneid (CC)

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In a Flash: How You Can Help Fireflies

Growing up in Argentina I remember the summer nights coming home from visiting my grandparents in the country, and looking out into the darkness of the fields, briefly lit up by fireflies. I remember that even though the drive was long (for my child-time perception), I was always looking forward to it and wanted it to never end… Those lights were so magical! How was it even possible that small little insects could create such a whimsical view?

I grew up and moved to other places where fireflies were not present… until I moved to Maryland. My first summer here (and all the following summers, really), I would look forward to those night lights, and then sit outside and just watch them again and again. The excitement I had when traveling back from my grandparents’ is still fresh in me, and I wonder every time at the little insects, no matter how many times I have seen them. In today’s post, I wanted to share some cool resources that will help you find another excuse to continue watching them, learn to recognize the different species and protect them through a variety of ways.

Fireflies from here

North America harbors a very large number of species of fireflies. Among the over 150 species present across the continent, about 15 are known to occur in Maryland (on iNaturalist you can see more details). Although most species prefer relatively humid conditions (e.g., close proximity to creeks or moist areas), they all differ by when they are actively producing light (for example, dusk vs. the night) or their flashing patterns (you can learn a lot more about their biology and behavior from  Mass Audubon).

images of the different fireflies in Maryland
Several species are known to be present in Maryland. Photo:

Love watching fireflies?

Today, the diversity, ranges, and even conservation status of many fireflies in North America are not well understood. This is problematic because studies appear to show that many species may be declining. However, without clear information on where the different species occur and when they are active, it is really hard to know whether species are likely in need of conservation or not. However, given how large the continent is and how fireflies appear to be present in many regions of the country, it is challenging for scientists to get this information efficiently… or is it?

To address this need, some groups of scientists started a set of projects that rely on what we call citizen science. Here, citizens from around the country can voluntarily sign up, go outside in the evening and watch for fireflies, and then submit their observations to the projects. Anybody can participate in these projects, so we can all actually help the scientists help the fireflies, just by taking part in the studies! The projects that are currently happening in our area are slightly different in scope. Let’s see what each one is trying to do.

This project receives both incidental observations (e.g., you were walking and saw a firefly) and information from structured surveys that are geographically restricted to specific targeted areas (one of which includes most of Central and Eastern Maryland). This project is also seeking to gather information in particular about specific species that are suspected to need conservation or need more data in that particular region. Although participation in incidental observations is simpler than in one of the targeted surveys, both are really useful to the scientists. Either way, the project offers a lot of resources to learn how to identify fireflies and will also help you confirm the identifications once they have been submitted. For both participation types, one has to register and create an account, so all submissions can be properly identified and databased. To get to know about this project, and access its resources, visit the Firefly Atlas website.

This project seeks to understand the population trends of fireflies and the potential reasons for those changes. This project is open to anybody who would like to participate and receives observations from any region of North America. Participants engage in performing 10-minute-long surveys once a week during the firefly season. These observations can be done from anywhere (e.g., your backyard, a forest) and even not seeing any fireflies is useful information! To participate, interested people need to create an account, and then become familiar with the number of flash patterns that they may encounter (a neat chart is shared to learn this). Finally, they need to implement a very easy-to-do protocol and submit their results. To earn more about how to participate, check out the Firefly Watch website.

I want to help the fireflies, but I don’t have the time or ability to take on these projects

Although many things are left to understand about firefly biology, scientists already know that some threats exist. If we want to help them, and while we learn more about their ecologies and needs, we can do so by acting to address these threats in our everyday lives.

As for other insects and biodiversity, habitat loss and pesticide use are important threats to their survival. Increasing the diversity of habitats in our green spaces and choosing non-pesticide solutions when possible are great ways to help them! Another threat that is particularly important for fireflies is light pollution. Because fireflies use light to communicate with each other, if we have a lot of lights on during the night, we can prevent them from finding each other, interfering with their reproduction and thus reducing their ability to sustain their populations. Turning off all unessential lights (e.g., accent lights, light strings) present in our green spaces at night can go a long way, while even saving us some money.

By Anahí Espíndola, Assistant 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,, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

The value of a pile of sticks in your yard or garden

With spring coming up, many of us are already starting to get our yards and gardens ready for the growing season. Among the activities we may take on, there can be the managing of branches, sticks, and wood that may have been trimmed from trees and shrubs in the fall, over the winter, or just recently. In today’s post, I want to talk about how to integrate these resources into our green spaces, to support wildlife and the natural services they provide.

a pile of stick in a yard
Wood and stick piles can provide welcoming habitat to beneficial organisms. Photo: A. Espíndola

Increasing the diversity of our green spaces

In several of the posts that we publish on this blog, we recommend different actions that can be taken to increase biodiversity in our green spaces (see local ecotype plants, helping pollinators in small green spaces, and conserving parasitoids for some ideas). We know that increasing biodiversity improves the ability to control and restrain pests, increases wild and crop plant pollination, and in many cases leads to better soil quality. Among these practices, there is one that increases the physical complexity of our green spaces, providing nesting, shelter, and food resources to beneficial organisms. The practice I’m talking about consists of building wood and stick piles that can be established in our green spaces. The idea behind this practice is to create a space where birds, small mammals, insects, and even pest predators can find their preferred resources, and thus be attracted and present in our environments (learn more about the landscaping rationale for using dead wood).

What organisms are attracted by these piles?

Depending on the size of the pile and its composition (e.g., large logs, smaller sticks, a mix of them), different organisms will be attracted and may establish themselves in our green spaces. The presence of a mix of logs and sticks usually attracts birds, which may nest within the pile or may just spend time within the pile searching for food or finding shelter at different points during the day. These birds will certainly contribute to increasing the diversity of animals present in our green spaces and can also in some cases participate in the control of insect pests that we may not want in our gardens and yards.

Carolina wren bird with a caterpillar in its mouth
Carolina wrens are very attracted to shrubby habitats, meaning that piles of wood and brush represent a great way to provide resources to these little cute birds who in turn can help us keep herbivore populations in line. Photo: Shenandoah NP.

Other animals we can observe in these piles are a variety of insects then may be associated with the decomposition of wood or that may use wood as a nesting or overwintering resource (e.g., bees, solitary wasps). While the former can help recycle the wood material and reintegrate it into the habitat, the latter may participate in the pollination of plants and crops that we may grow in that area or predate on unwanted pests.

Similarly, ground-dwelling invertebrates like millipedes and ground beetles can also find shelter under these piles, while the brush can also contribute to the nesting of pollinators such as (ground-nesting) bees, the overwintering of some butterflies and moths, and help improve the quality of the soil in that part of our yard.

Larger organisms may also be attracted to these piles, such as small mammals, amphibians, and even reptiles. Although we may tend to dislike these groups of animals, many of them feed on unwanted soil organisms and may help with soil quality, while others can actually control vermin through their predatory abilities. This is particularly the case of snakes that may find shelter in these spaces, which, while harmless to humans (the vast majority of snakes in Maryland are non-venomous, readily feed on rats and mice that may be present around the house.

a pile of wood branches and sticks in a yard makes a habitat for beneficial organisms
A mix of thick and thin pieces of wood can provide a diverse habitat to many different organisms. Photo: A. Espíndola.

How to build these piles?

These piles can take many different shapes and sizes, which depend in part on the materials and space available. When very large spaces are available (e.g., in the woods), it is recommended for these piles to be relatively large – at least 10 to 20 feet in length, and up to 8 feet in height (read more about these larger brush piles). In smaller spaces such as in urban or suburban gardens, these piles can be much smaller, occupying areas that may not be regularly used for other purposes. In all cases, it is ideal to build these piles using a combination of different types of materials, such as twigs and branches of different thicknesses, some logs, and even some branches that may still have dead leaves attached to them…always using healthy materials.

An important consideration when putting together these piles is that they should not be built leaning on or very close to wood-based structures or the foundations of our buildings. This is because of the potential risk of termite infestations of buildings if the piles are not physically separated from them. However, it is important to stress that establishing these piles has not been shown to be associated with higher termite infestations if the pile is not in contact or very close to the built structure. (You can read a very good discussion about mulch and termites from Iowa State Extension).

So, as you work on your spring garden, I encourage you to think about plant stems, logs, and branches not as waste that needs to be cleaned up, but as beneficial resources that you can incorporate into your available space.

By Anahí Espíndola, Assistant 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,, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Thinking about getting honeybees? Some food for thought

With the huge losses of biodiversity that we are seeing across the world, a prominent example that became very close to people’s hearts is that of the large pollinator losses and the very important consequences that they could have on the well-being of our ecosystems and ourselves. In this context, a very large movement started seeking to “save the bees,” which has had a number of expected and unexpected consequences. One of the latter is the very significant increase in the adoption of honeybee hives by homeowners with little to no experience in honeybee husbandry, especially with the goal to “help bees” so they won’t go extinct. Although the goal of doing this is very genuine and well-intentioned, there are a number of complexities that come with this decision, which I would like to talk about in this post.

Are the bees dying?

The short answer is yes… kind of. Let me explain. As we mentioned in previous posts, there exists a very large diversity of bees (for example, only in Maryland there are about 400 native bee species!), and it is very clear that trends in biodiversity are negative for bees, as for many other groups of insects, plants and other animals. From that respect, we can say that many native bees are indeed dying, and it is key that actions are taken to provide more healthy habitat for them to survive.

That said, it is important to understand that honeybees are actually non-native livestock in our region (the group of bees that honeybees belong to are native to Eurasia and Africa, not to North America). Honeybees are managed and non-native insects that are reared by beekeepers to produce honey and other materials (e.g., wax, propolis). In places where honeybees are native, local peoples have been using their materials for generations, and in those regions, honeybees have not only been important from a production perspective, but also from a cultural one (read here to learn a bit more about some of these traditional systems).

As for all livestock, honeybees have health issues that need to be treated if they occur. For example, honeybees suffer from serious parasite and viral infections, appear to be negatively affected by certain pesticides applied to the plants they collect pollen and nectar from, and seem to also be affected by environmental stressors such as changes in the diversity of the landscape and the quality of the plants they feed on. All of this increases the real potential to reduce the health of colonies and, if left untreated, decimate them.

bee on orange milkweed flowers
Photo: M. LaBar (CC).

Will I help the bees if I get honeybees?

Again, the short answer is probably not. As I was saying above, honeybees are non-native to our region, so increasing their populations (for example, by increasing the number of hives) in our region is not likely to positively affect our suffering native species. For example, it has been shown in some studies that honeybees can be pretty competitive in the way they visit plants, displacing native species. Further, and especially if the honeybees are not properly managed (which is, unfortunately, the case for many new unexperienced beekeepers), they can become sick and spread diseases to native bees and other insects, also leading to increasing the pressures on these already-struggling native organisms.

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Trees & shrubs for pollinators

For some reason, I feel that every time I think about what to plant for pollinators, the list of plants that comes to me is one full of herbaceous ones… however, it is odd that this is the case, because it’s not like our region lacks larger plants (e.g., trees, large shrubs) that are both fully able to support pollinators while also supporting other biodiversity and even contributing to flood and rain management! And because if we’re interested in going the large(r)-plant path, we need a bit of planning, in today’s post I would like to present some native shrubs and trees that are great resources for our pollinators. This way, you can start planning where to get them for planting in late winter to early spring.

Why consider trees and shrubs for pollinators?

Large perennial plants such as trees and shrubs have many characteristics that make them very attractive to any pollinator-friendly person in our region. Indeed, while there are many of these plants that act as wonderful food resources for many pollinators (both adult and larval stages), these larger plants represent long(er)-term and abundant resources that can serve different aspects of our ecosystem: they provide shelter and food for birds, they can assist in managing stormwater runoff, retain soil, reduce surface temperatures by their shading abilities, and provide structural complexity to our landscapes. Trees especially are a key component of creating climate-resilient landscapes. In fact, one of Maryland’s climate change mitigation goals is to grow 5 million more trees by 2031!

Planting trees is not necessarily expensive

From a financial perspective, although these plants may be costlier to obtain than the smaller herbaceous ones, there is a multitude of incentives, state vouchers, and programs that strongly reduce or sometimes completely cover the costs of obtaining them. In Maryland, for example, the state provides incentives through the Maryland Department of Natural Resources (discounts to be used at nurseries; all details here), the PG County Rain Check program or the TreeMontgomery program, city incentives, and free tree plantings (e.g., see College Park’s here). In all of these programs, a lot of trees native to our region are covered. If you would like to participate in any of these programs, make sure to check the specific tree lists covered by each (also, see this list of recommended native trees for the state of Maryland). Note that these programs I mentioned here are just a few of the many that exist; if you’re interested in this, make sure to check your city, county, and state resources!

What to plant?

I hope by now I have at least made you curious about the idea of choosing trees and shrubs for pollinators. Below, I made a very small selection of a couple of plants that appear in the native lists, and that are great for pollinators. Let’s take a look at them.

Tulip tree (Liriodendron tulipifera)

Tulip trees are a great native plant that can serve as a great pollinator resource. This tree is in the same family as Magnolia trees. It can reach a large size and it displays stunning yellow and orange flowers. This tree grows fast and is large (considered the tallest native tree in the eastern USA, along with sweetgums), so it can be a good choice for large spaces where a canopy is wanted relatively quickly. The flowers produce a lot of nectar, which attracts a massive number of pollinators. This makes it kind of fun to stand under the tree on warmer days during the blooming time: the buzzing coming from the tree is pretty impressive. Here are some more details on the conditions preferred by this tree.

the yellow and orange flower of a tulip tree
Tulip trees are among the tallest trees in the eastern USA and have wonderful resources for pollinators that they carry in their stunning flowers. Photo: W. Cutler CC.

American linden or basswood (Tilia Americana)

This tree can reach relatively large sizes, and when it grows to full size it has a very rounded canopy. I personally love this tree, because of the fact that I feel it’s a “social” tree: one can sit with friends under its shade on hot summer days, and just enjoy the life it hosts and the cool breeze it forms under it. Once the season is coming to an end, this tree’s leaves turn a lovely yellow. The flowers of this tree are small and not very colorful, but they are extremely fragrant and full of nectar, which makes them a great magnet for pollinators. You can learn more about the requirements of this tree at Virginia Tech Dendrology.

white flowers blooming on American linden tree
The American linden has discrete flowers that are very attractive to pollinators. Photo: A. Zharkikh CC.

Hawthorns (Crataegus phaenopyrum and C. viridis)

These are mid-size trees that also sustain a variety of fauna through their flowers, fruits, and bird nest-friendly thorny branches. Their flowers are white, have a typical Rose-family structure (like those of cherry trees), and are attractive to bees, syrphids, butterflies, and hummingbirds. Besides being great for fauna, the two species do well in urban environments, because they both tolerate a wide variety of conditions. Here at and on the Lady Bird Johnson Wildlife Center website you can learn more about each of these species.

White flowers of a hawthorn tree in bloom
Hawthorns have lovely white flower clusters. Photo: F. D. Richards CC.

Fringe tree (Chionanthus virginicus)

This small tree/tall shrub is a great addition to green spaces, and is ideal for hedgerows or just as a stand-alone plant. I am always surprised by the super cool shape of the flowers of this plant, which have very elongated petals that create long white fringes. These flowers attract bees and other pollinators, which come to collect some of the nectar that is produced. This plant is usually dioecious, meaning that one individual plant harbors either male or female flowers, but rarely both. This plant is ideal for areas that receive a lot of sun, because it is under those conditions that it will do best (although it can do fine in less-sunny areas as well). You can learn more about this plant by visiting this website.

white flowers of the fringe tree
The whimsical flowers of fringe trees are not just attractive to us, but also to many pollinators! Photo: 阿橋 HQ CC.

Serviceberry (Amelanchier laevis)

Although all of them can provide very good resources for pollinators, I picked this one to showcase because this species grows relatively fast and does not get too large. This is indeed a larger shrub that has beautiful white flowers, and later on, delicious small berries. Because of all this good stuff, the flowers are visited by many insects, and the fruits are favorites of birds (so you’ll have to win over them if you want to get at the fruits! 😉 ). Here and on the University of Maryland Extension website, you can learn a bit more about this cool plant.

Serviceberries make everybody happy: pollinators in the spring with their flowers, and birds and humans in the summer with their berries! Photo: Henna K. CC.

By Anahí Espíndola, Assistant 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,, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!