sustainable landscaping

Trees & shrubs for pollinators

December 12, 2022January 23, 2023Maryland Grows4 Comments

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 pollenlibrary.com 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, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

We are still alive! How to protect pollinators in the slow season

November 14, 2022November 22, 2022Maryland Grows1 Comment

Even when they look dry and “dead,” our green spaces are full of life. When we think about plants, for example, we can see that herbaceous perennials seem dry but they are actually just retreating underground, while annuals continue their life cycle by spending the winter as seeds in the ground. The same is true for other organisms that live in our green spaces: squirrels become less active, snakes retreat to sheltered spaces, and insects may overwinter as adults underground or in crevasses or as juveniles in their nests or chrysalises. Among these insects, there is a particular group that we seem to take a lot of effort to protect in season, but that we may then forget about in the fall and winter: our pollinators. In today’s post, I would like to talk about some specific ways that allow us to take care of our green spaces in the fall, all while continuing to support these organisms we worked so hard to support throughout the growing season.

Where are our pollinators in the winter?

As we mentioned in a previous post, pollinators don’t disappear in the winter. Instead, they either migrate to warmer conditions (like monarchs do; check out this website to know where they are now!) or stick around and overwinter right here in protected spaces such as crevasses, underground nests, and within plant stems. If we have been enjoying supporting them throughout the season, it may be a good idea to continue to do so also throughout the winter. Let’s see some ways to do this.

Continue reading →

Maryland gardeners are adapting to climate change

August 18, 2022August 17, 2022Maryland GrowsLeave a comment

How are Maryland gardeners adapting their gardens and green spaces to climate change? We posed this question to our colleagues in the University of Maryland College of Agriculture and Natural Resources and several of them shared examples of everything from composting and food gardening to planting trees and native plants, installing rain gardens, and more.

Action on climate change is needed on a large scale, and our individual actions at home and in our communities all add up too. Check out our Story Map showcasing the variety of ways Marylanders are adapting their green spaces with climate change and sustainability in mind. Then take our quick poll at the end of the Story Map and let us know: Are you doing climate-resilient gardening?

Screen shot of the climate-resilient gardening story map

View the Story Map

Learn more:

By Christa K. Carignan, Coordinator, Digital Horticulture Education, University of Maryland Extension Home & Garden Information Center. Read more posts by Christa.

The more the merrier: community actions for pollinators

June 13, 2022June 9, 2022Maryland Grows1 Comment

Besides it being the month when summer starts, June is a great month because it is when Pollinator Week happens! 😊

Tagging along with that week, in today’s post I want to talk about some actions you can take with(in) your community to help pollinators! Because, if we want to help pollinators, a very valid and effective way to amplify your actions is to get others on board! Here, a non-extensive list of ideas.

1. Become a Bee City

Ask your City or Campus to become a certified Bee City or Bee Campus USA. Bee Cities and Campuses are certifications that cities and campuses across the USA can obtain if they implement a series of actions (“commitments”) established by the Xerces Society. Once these actions are done, the City or Campus in question becomes certified as a pollinator-friendly space. The types of actions outlined are really activities that lead to increasing education on pollinators and pollination, to improving pollinator habitat on the institution’s land, to promoting actions in the way that the institution functions that may allow for increasing pollinator support (see here for city commitments and here for campus commitments). Becoming a Bee City or Campus is not hard, and most institutions say yes if their members ask. If you think this is something you would like your City and/or Campus to do, reach out to your representatives or leadership and get them on board! And to have an idea of what cities and campuses are already involved, take a look at the Bee City USA affiliates.

2. Organize a Pollinator Week Event

Pollinator Week is a National event organized by the Pollinator Partnership and includes many possible actions that lead to increasing pollinator survival and/or awareness. This year, Pollinator Week will be happening June 20-26. One can participate in activities already organized by others, or one can propose and host an activity! If you would like to get together with your community and organize an event, do it, and then submit it to the Pollinator Week event list! That way, others will know about it and will participate as well! To submit (or participate in) an event, go to the bottom of the Pollinator Partnership page.

Here are some activities happening in Maryland: bee hotel building workshop in College Park, MD, webinar in Greenbelt, MD, pollinator catch-and-release in Saint Leonard, MD, and several activities in Howard Co., MD.

3. Ask your city to host a No-Mow Month in early-spring

Early-spring pollinators emerge usually when very few plants are flowering, meaning that the early spring is a critical time for these pollinators. In human-occupied landscapes like cities or suburban areas, a lot of the landscape is occupied by lawns, which can provide some flowers early in the spring. No-Mow Month (usually April or May, depending on the city’s conditions) is an action that seeks to allow the availability of the early flowers in lawns so that local pollinators can survive during the early spring. Once other plants in the landscape start flowering (usually at the end of April in most of Maryland), the lawn can be mowed with this not negatively affecting pollinators.

It is important to note that this action is based on voluntary participation, meaning that participants opt-in (instead of being mandated to do it). This action has been shown to be effective in increasing pollinator diversity and abundance in regions where it is implemented, and is not associated with excessive lawn growth because it occurs so early in the season. Further, it can be strengthened with native plantings, which can boost its effects and also support local landscapers during the reduced-mow month. Localities where the action has been implemented tend to have high adoption rates, increased nature awareness, and willingness to further support biodiversity around homesteads, with no- to very-reduced vermin occurrence.

This action usually requires some temporal amendments to City Code (e.g., to ensure that participants will not be penalized if their lawns surpass the maximum allowed height during the no-mow month) so it needs approval by City Councils. Although this may sound really complicated, it is not, and several Cities in Maryland have implemented this program very successfully during the month of April (see here for College Park, MD, and here for Greenbelt, MD), following Appleton, WI’s trailblazing action. If you think this is something you would like to implement in your community, get in touch with these cities’ Bee City USA committees so they can share their expertise, and then contact your representatives to ask them to adopt this action where you live!

4. Ask your community to establish pollinator-friendly plants and nesting resources

Communities can also support pollinators through the way they decide to landscape their land. Requesting your community leadership to implement pollinator-friendly gardens and offer nesting resources for pollinators (e.g., bee hotels, create small wild spaces) is a really good way to help pollinators at a larger scale. To do this, you can get in touch with you City/Town Horticulturist and/or Public Works people, and request this. If you would like to implement this in your neighborhood and on private land, you can coordinate with your neighbors and create plots of native plants or small nesting areas in everybody’s green spaces. A very effective way to do this in Maryland is by establishing a neighborhood Green Team. If you would like to know about how to do this, take a look at this page of recommended native plants and this list of native plants that do well in our area.

Chart listing easy-to-grow native plants that support pollinators

5. Ask you city/town/neighborhood to adopt an IPM plan

Although we tend to think about helping pollinators only by planting flowers and maybe creating nesting spaces, pollinators also can be helped by the way we manage our landscapes. For example, herbicides and pesticides can be sometimes very harmful to pollinators, or cutting plants at certain times of the year can really negatively affect them. Reducing the use of pesticides and herbicides, or changing the way we manage our own private land is one possibility. However, cities, towns, neighborhoods, schools, and campuses also manage their public lands! For that reason, they can also implement actions to manage spaces in ways that support pollinators.

chart explaining Integrated Pest Management in 5 steps

A very good way to institutionalize this is by requesting these institution to implement Integrated Pest Management (IPM) plans. IPM is a way of controlling pests and increasing “beneficial” organisms in a given space by means that reduce the use of pesticides and herbicides. These plans establish a framework that allows institutions to still control pests and diseases, while reducing the negative impacts on biodiversity that some conventional practices have. These plans can be very general or very specific, and if your institution does not have one, it may be time to ask them to implement one! To do this, get in touch with your institutional horticulturist or your government representative. Here are some examples: city, campus and school district plans.

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, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Q&A: How Can I Make a Naturalistic Garden Look Intentional?

April 8, 2019April 5, 2019Maryland Grows3 Comments

blue sedge — *Blue sedge. Photo: Ellen Nibali*

Q: I would like to plant a more natural garden but am worried about irritating the neighbors who might think it is sloppy or not a garden at all! Any advice?

A: Make a natural garden look intentional. Here are three major design tips to make a garden’s intent obvious:

1) Give it obvious edges. Edges can be botanical, such as a row of blue sedges (pictured) or can be hardscapes such as pavers, bricks, a path, low wall, or low fencing.

2) Give it an obvious shape. This can be geometrical lines and angles (circle, triangle, parallelogram, etc.) but also can be flowing lines made obvious with big or repeated curves.

3) Within the beds, make plant choices obvious. Use blocks or ribbons of plants, repetition of key species, or a predominant plant family (e.g. grasses) with a few other species mixed in. Of course, banish all invasive plants. Use at least 70 percent native plants.

By Ellen Nibali, Horticulturist, University of Maryland Extension Home and Garden Information Center. Ellen writes the Garden Q&A for The Baltimore Sun.

Do you have a gardening question? University of Maryland Extension experts have answers! Send your questions and photos to Ask an Expert.