The Pollinator-Tree Connection: More Than Just a Pretty Canopy

Looking at Trees in a New Way to Support Urban Canopy Goals

When we think about planting trees in urban areas, the focus has often been on aesthetics, shade, and increasing property values. While these are important benefits, trees can do even more for our communities - especially when selected strategically. By planting trees that support pollinators, we can help rebuild essential ecosystems, improve biodiversity, and create a more resilient urban forest. Trees are more than passive landscape elements (or our favorite places to hang a hammock); they can serve as critical resources for bees, butterflies, and other beneficial insects.

CanopyBloomington is leading the charge in supporting Bloomington’s urban forest by looking at trees through a new lens. Their work strengthens local biodiversity and enhances the conventional benefits of tree planting, such as cleaner air, cooler streets, and healthier communities. With your help, we can grow an urban canopy that sustains both people and pollinators.

The Connection Between Trees and Pollinators

Pollinators are essential to the health of natural and urban ecosystems, helping to fertilize plants that produce fruits, seeds, and nuts. Between 75% and 95% of flowering plants rely on pollinators for reproduction, including over 180,000 plant species and 1,200 crops. In fact, pollinators are responsible for about one-third of the food we eat1. Take a walk outside and observe the trees in your yard or a nearby park or greenspace. You might spot a summer azure2 fluttering by, and if you're lucky, a luna moth3 resting near a sweetgum tree - an essential host for its caterpillars.

Trees play a fundamental role in supporting these vital creatures. Many native trees (like two of my springtime favorites, redbuds and dogwoods) bloom early in the year, offering nectar and pollen when other floral resources are scarce. Additionally, certain tree species (like the sweetgum I mentioned earlier, or birches, hickories, and more) act as host plants for the caterpillars of butterflies and moths, providing critical food sources that support their full life cycles. By thinking about pollinators during urban planning, we can create landscapes that sustain these species while also taking advantage of the environmental, economic, and social benefits of a thriving tree canopy.

Choosing the Right Trees for Pollinators

Selecting appropriate tree species is essential for creating a pollinator-friendly environment. Native trees are particularly beneficial as they have co-evolved with local pollinators. Below are some native Indiana trees recommended by CanopyBloomington, along with their roles as host plants and the pollinators they support:

White Oak (Quercus alba)

Description: A large deciduous tree reaching 50 to 80 feet in height, with a broad, rounded crown and reddish-brown fall color.

Pollinator Benefits: Oaks are host plants for numerous butterfly and moth species, including the Eastern Tiger Swallowtail4 and Red-spotted Purple5. The larvae of these species feed on oak leaves, making the tree a critical component of their life cycle.

Did you know: There are 18 different species oaks native to Indiana? That can make identification a bit challenging.

Hackberry (Celtis occidentalis)

Description: A medium to large deciduous tree, 40 to 60 feet tall, with a rounded or vase-shaped crown and yellow-green fall color.

Pollinator Benefits: Hackberry trees serve as host plants for butterflies such as the Hackberry Emperor6 and the Tawny Emperor7. These butterflies lay their eggs on hackberry leaves, which provide food for the emerging caterpillars.

Kentucky Coffeetree (Gymnocladus dioica)

Description: A tall deciduous tree growing 60 to 80 feet high, featuring rough, scaly gray-brown bark and large compound leaves that turn yellow in the fall.

Pollinator Benefits: While not a primary host plant, the Kentucky Coffeetree's late spring flowers attract various pollinators, including bees, due to their nectar production.

Did you know: Don’t let the name fool you, Kentucky Coffeetree isn’t good for drinking. The seed pods are best left to be admired from afar, and the timber is better suited for construction or furniture making.

Red Maple (Acer rubrum)

Description: A fast-growing tree, reaching 40 to 70 feet tall, known for its striking red foliage in the fall and early spring flowers.

Pollinator Benefits: One of the earliest trees to bloom, red maple provides an essential nectar source for bees when other flowers are scarce. While not a host plant for many butterfly species, its flowers support early-season pollinators such as native bumblebees.

Eastern Redbud (Cercis canadensis)

Description: A small ornamental tree, 20 to 30 feet tall, featuring heart-shaped leaves and striking pink-purple flowers in early spring.

Pollinator Benefits: Redbuds bloom before most other trees, offering nectar for bees, including mason bees and bumblebees. Additionally, redbuds serve as host plants for the Henry’s Elfin butterfly8, whose caterpillars feed on the tree’s young leaves.

Driving around Bloomington in the spring, you can’t miss seeing these beautiful blooms everywhere - always a sign that spring has sprung. Take a walk along the Clear Creek Trail some time in February through May for a spectacular show.

Yellowwood (Cladrastis kentukea)

Description: A medium-sized tree, 30 to 50 feet tall, with a rounded crown and yellow-orange fall foliage. It produces showy, fragrant white flowers in late spring.

Pollinator Benefits: The fragrant flowers of the Yellowwood attract bees and other pollinators. While not a significant host plant for butterfly or moth larvae, its nectar-rich blooms provide a valuable food source for adult pollinators.

Did you know: In Indiana, the Yellowwood tree is known to naturally occur only in Brown County, home to the state forest that bears their name.

By incorporating these native trees into urban landscapes, we can provide essential resources for pollinators throughout their life cycles. CanopyBloomington offers resources and tree-planting programs to help residents and businesses make informed choices that benefit both pollinators and the broader community.

Expanding Beyond Trees: Layering Habitat

To create a more supportive environment for pollinators, it's beneficial to include a variety of plants at different heights and seasons. Understory shrubs, perennials, and ground covers can offer additional nectar, pollen, and habitat. Consider integrating the following:

Native Shrubs: Species like American Hazelnut (Corylus americana) and Spicebush (Lindera benzoin) provide early-season blooms and serve as host plants for certain butterfly species, such as the Spicebush Swallowtail9.

Spicebush also smells delightful and grows happily in that hard-to-fill shady spot in your yard.

Perennials: Milkweeds (Asclepias spp.) are host plants for the monarch butterfly10, which is proposed for protection under the Endangered Species Act. Other plants like Purple Coneflower (Echinacea purpurea) and Wild Bergamot (Monarda fistulosa) offer mid to late-season nectar sources and attract a variety of pollinators as well.

To maximize your butterfly observations, try a combination of flowers that bloom at different times of the year from early spring through the end of fall.

Ground Covers: Options such as Wild Strawberry (Fragaria virginiana) not only provide nectar but also produce fruits that feed other wildlife.

This layered planting approach ensures that pollinators have access to food and shelter throughout the growing season. For help getting started, take a look at these Midwest Habitat Hero Native Garden kits. Designed with pollinators in mind, these kits also support a scholarship fund by donating one plant for every four sold - promoting education, expanding access to native plants, and strengthening community engagement in pollinator habitat enhancement.

The Added Benefits for Communities

Beyond supporting pollinators, planting native trees and plants offers numerous benefits to communities:

Environmental Advantages: Trees improve air quality by absorbing pollutants, sequester carbon dioxide, and aid in stormwater management by reducing runoff. In Bloomington, the existing tree canopy sequesters approximately 28,000 tons of carbon annually, removes 470,000 pounds of air pollutants, and manages 90.6 million gallons of stormwater runoff each year, providing an annual economic value of $1.9 million to the city11,12.

Economic Benefits: Healthy urban canopies can increase property values, reduce energy costs by providing shade, and decrease infrastructure expenses related to stormwater management. Bloomington's tree canopy is valued at nearly $55 million in ecological and economic benefits12.

Social and Health Benefits: Green spaces with diverse plant life enhance the aesthetic appeal of neighborhoods, provide recreational opportunities, and have been linked to improved mental health and well-being. In Bloomington, trees have been shown to boost the immune system, reduce deaths from heart attacks, strokes, and lower-respiratory diseases, promote better sleep, and reduce mental stress and anxiety13.

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Take Action with CanopyBloomington

Investing in Bloomington’s urban canopy is an investment in the city's future. CanopyBloomington works year-round to plant and protect trees that benefit pollinators, improve air and water quality, and make neighborhoods healthier and more beautiful. But we can’t do it alone.

By donating to CanopyBloomington, you help fund tree-planting initiatives, educational programs, and community engagement efforts that make a lasting impact. Whether you contribute financially, volunteer for a planting event, or participate in our tree adoption programs, your involvement directly supports a greener, more pollinator-friendly Bloomington.

Join us in creating a thriving urban canopy that works for both people and pollinators. Visit CanopyBloomington.org to learn more and make a donation today.

ANDY GRINSTEAD

Andy Grinstead is a CanopyBloomington board member and community steward who is dedicated to fostering equitable access to natural resources and nature-based experiences. He currently works with the non-profit Pollinator Partnership managing habitat enhancement, ecological restoration, technical certification, and outreach programs throughout the country.

Additionally, Andy is a member of the Monroe County Environmental Commission, advocating for educational efforts and initiatives that support a healthier and more economically viable future for the county. Andy enjoys sharing his enthusiasm for collaborative engagement and volunteerism with the CanopyBloomington community.