What to Know About Native Trees and Butterflies

Native Trees for Butterflies

By Joanna Brichetto
Tennessee Naturalist
SidewalkNature.com

Did you know that native trees help “make” butterflies?

For example, our Tennessee State butterfly, the Zebra Swallowtail, can lay eggs only on Pawpaw: a native fruit tree. No other plant will do. The newly hatched caterpillars eat nothing but Pawpaw leaves until they are old enough to form a chrysalis. Likewise, Spicebush Swallowtails lay eggs only on Spicebush and Sassafras. Olive hairstreak butterflies use Eastern red-cedar, and Spring Azures need native Dogwoods.

All butterfly larvae—the very hungry caterpillars—need the right baby food to survive. They only eat leaves of select plants with which they’ve co-evolved. A butterfly mom knows this, so when it is time to lay eggs, she searches for the native plants she needs.

The fancy term for this specialized relationship is “larval host plant.” A plant is a host if it feeds the larval stages of an insect. Take milkweed, for instance: the host that Monarch caterpillars can’t live without.

Not all caterpillars are such picky eaters. Another showy butterfly, the Eastern Tiger Swallowtail, can lay eggs on several native trees, including Tulip poplar, Black cherry, Sweetbay magnolia, Hawthorn and Serviceberry. Red-Spotted Purples can use Willows, Black cherry, Cottonwood and others.

Even our humble Hackberry tree is a larval host for butterflies. Leaves feed the Tawny Emperor, American Snout, Question Mark, Mourning Cloak and the “social butterfly” most likely to hitch a ride on a passing human: the Hackberry Emperor.

Oak Trees: Hosts with the Most

The trees that host the most butterfly and moth species are our native oaks, cherries, willows, maples, hickories and crabapples. If you’ve only got room for one new tree in your yard, make it an oak: the top producer in any foodweb. A native oak in Middle Tennessee can host over 400 species of butterflies and moths!

Contrast such hospitality with non-native trees. Here, a ginkgo, crepe myrtle, Japanese maple, Yoshino cherry or other exotic cannot compete. They’ve evolved on other continents with their own specialized relationships, and so cannot fully support a foodweb here. This is another reminder that native plants are the foundation of all local ecosystems.

What about butterfly grownups? Do trees help them, too? Yes! With shelter and water, and sometimes with nectar. Native trees that bloom during butterfly season include Tulip poplar, Basswood, Persimmon, Sourwood, Elder, Buttonbush, Hawthorn and the Rough-leaved and Silky Dogwoods.

Doing Your Part

How can YOU help make butterflies? Here are a few ways to get started:

• First, do no harm. Skip the herbicide and pesticide on your lawn, shrubs, trees and flowers. Despite aggressive advertising, mosquito fogging won’t make a dent in mosquito control but will kill non-target wildlife like fireflies, butterflies, bees and ladybugs. Instead, use common-sense mosquito prevention tactics.

• Plant native. Try to add at least one new native plant every year.

• Convert a 4x4’ patch of lawn into a Pollinator Garden with native host plants and nectar flowers. Don’t be too tidy: winter seed-heads feed birds, and dead stalks hide hibernating bees.

• Leave the leaves. Many caterpillars and pupae wait out the winter in leaf litter. Instead of mowing, blowing, and bagging, move your leaves to garden beds and tree roots.

Resources:

To learn which trees (and other plants) are native to our area, type your zip code into the National Wildlife Federation Native Plant Finder. The butterfly icon shows how many species a genus hosts.

Shop for native trees during the NTCC Farm-to-Yard Tree Sale. Select the “Native” tag to see trees offered in this category.

Or try one of our local, all-native nurseries GroWild, Inc. and Nashville Natives.

For a quick, printable list of host and nectar plants for Middle Tennessee, see this list from the North American Butterfly Association.

For a comprehensive (and beautiful) butterfly field guide, see Butterflies of Tennessee: Field and Garden, by Rita Venable.

Joanna Brichetto is a certified Tennessee Naturalist in Nashville, where she writes about everyday wonders in everyday habitat loss. Her essays have appeared in Brevity, Fourth Genre, The Hopper and other journals; and her current project is an urban-nature almanac called Hackberry Appreciation Society. Follow her on Instagram (@Jo_Brichetto) and at SidewalkNature.com.