Pictured above: Question Mark, American Snout, and Mourning Cloak, which utilize Hackberry as a larval host plant.
Did you know that trees are important butterfly host plants? Many are hosts for the larval (caterpillar) stage of the butterfly. The adult butterfly lays its eggs on the leaves. When they hatch, the caterpillars munch away. The feeding does not damage the tree. Often, the eggs are laid high in the canopy and you may never see them. Trees also provide butterflies protection during bad weather, a place for them to perch during the day, and a spot to roost at night.
Over 500 species of showy moths and butterflies are supported by oaks as a group. The species range from hairstreaks and duskywings to the showier species like the Polyphemus moth, the Blind-eye Sphinx, and Rosy Maple Moth. Even if you are not fascinated by the more mundane moths that oaks support, keep in mind that they are important food source for birds, frogs, and other insects.
But wait — there’s more! Many trees, in addition to Oaks, support butterflies — both the larval form and the adult. Let’s take a look at some of these trees and learn how to use them in your landscape.
American Hackberry Celtis Occidentalis
A small to moderate size shade tree, the fast-growing American Hackberry tolerates wind, urban conditions, and pollution. It adapts to occasionally soggy soil or extreme drought. Hackberry thrives in the rich, moist soil of floodplains, but can be found growing in average or even rocky soil. Its shady canopy is a good substitute for that of the Chinese or Siberian Elm. (It is in the Elm family, after all.) The corky bark provides visual interest all year long.
It can reach 70 feet and live for 200 or more years under good conditions. Its roots reach down 10 to 20 feet, enabling it to survive drought. It can tolerate sun or shade. In our experience, the leaves of hackberry are often yellow-ish by summer. We’ve come to enjoy its chartreuse teaser of fall in July.
Hackberry is a valuable larval host for Tawny Emperor, Hackberry Emperor, American Snout, Question Mark, and Mourning Cloak Butterflies. Many birds, from Mockingbirds to Cedar Waxwings, relish the small reddish-purple ‘berries’ that form on the tree in fall to winter.
Quercus palustris (Pin Oak)
Pin Oak is strongly pyramidal and often used in home landscapes. It is one of the faster growing oaks, growing 12’ to 15’ in 5 to 7 years. It is tolerant of wet soil, clay, and standing water for several weeks. Pin Oaks require acidic soil — leaves will yellow if the pH is too high. Even though it loves moisture, it is somewhat tolerant of summer drought.
It occurs naturally in wet woods and river bottoms. Clay is not a problem for this oak! A mature Pin Oak can reach 50 to 90 feet with a trunk 2 to 3 feet in diameter. Its leader, or central stem, does not fork. The acorns are sought by squirrels, woodpeckers, blue jays and more. This is an excellent lawn or street tree and grows quickly.
Easy to transplant, it attracts birds, butterflies, and hummingbirds. It thrives in moist to moderately dry soil and will eventually reach up to 80 feet in height. It does not need a tap root so transplants easily, and its naturally pyramidal shape is perfect for providing shade. The fall color ranges from red to burgundy.
The Polyphemus Moth (above) is one of many species supported by Oaks. Even as old oaks decline, their decaying branches support rich insect life.
Quercus Rubra Red Oak
Red Oak is another fast growing oak, growing up to two feet a year in moist well drained soil. When mature, it is round-topped and symmetrical. Easy to transplant, it prefers sandy loam, well drained, acidic soil. It withstands cold better than other oaks, but is a bit less drought tolerant.
Red Oak is a familiar oak, common in forests mixed with beech, linden, black birch, tulip tree, hickories and pines. It is the most shade tolerant of the oaks and attracts butterflies and hummingbirds. More than a thousand species of insects feed on the foliage of red oaks, according to Charles Fergus, author of Trees of Pennsylvania.
Red oak can reach 80 feet in height. It’s dark branches absorb winter sunlight and help melt snow off, making a striking scene on a cold blustery day. The trunk is limbless for the first half of its height, showing off its handsome smooth, striped bark.
Quercus macrocarpa Bur Oak
Bur Oak, the northern-most american oak, forms a broad crown when mature This large, majestic tree is adaptable to various soils: sandy, limestone, moist, dry, or clay. Unlike other oaks, it does not require acidic soil. Plant this oak if you have a high soil pH.
At maturity it reaches 70 to 80 feet, an individual trees can live 400 years. It’s dark leaves with lighter underside are an attractive feature in summer. It’s acorns sport a fringed cap, giving it a common name at times of ‘mossy-cup oak’.
It is one of the oaks that is a slow grower, perhaps adding on a foot of height a year, and develops into a spreading shade tree.
Quercus imbricaria Shingle Oak
The leaves of Shingle Oak with the Duskywing Skipper, one of the butterflies that rely on oak for larval food.
This oak tree does not have the typical oak leaves we expect. So we wrote an entire blog post about it! Check it out here.
Magnolia virginiana SweetBay Magnolia
Sweetbay magnolias are a host tree for the Eastern Tiger Swallowtail, Palamedes Swallowtail, Sweetbay Silkmoth and Spicebush Swallowtail. In late spring, they bear creamy white flowers with a sweet scent that merit savoring. The flowers appear sporadically over a few weeks, prolonging the fragrance.
They thrive in moist to wet soil, unlike many other magnolias. Sweetbay tolerates shade but prefers sun to part sun. This multi-stemmed, vase shaped small tree can reach 20 feet or a bit more. The dark, glossy leaves have a silvery underside. In mild winters they leaves may remain on the tree but it is not reliably evergreen and will push fresh new leaves each spring.
Salix Nigra Black Willow
Willows provide food in the larval stage for the Striped Hairstreak, Compton Tortoise Shell, Northern Pearly Eye, Cecropia Moth, Mourning Cloak, Red-spotted Purple, and Viceroy butterflies.
Black willow is a rugged, usually scraggly-looking shrub. It typically grows along streams, in flood plains, wet meadows and bottomlands. Often, it leans sideways and has branches at odd angles from the trunk. But don’t let its rough looks fool you, it performs several important jobs in the ecosystem, from streambank stabilization to supporting insects, butterflies, and birds.
Willows are some of the earliest plants to flower in spring, making them very important for pollinators. Another native willow, the pussy willow, is discussed here. Both willows are important butterfly host plants.
“Northern Pearly-eye – Lethe anthedon, Oc” (CC BY 2.0) by Judy Gallagher The Northern Pearly-eye is one of several butterfly species that willows support.
Amelanchier species Serviceberry
The Serviceberry is a host plant for Red-spotted Purple and Viceroy caterpillars, according to Save Our Monarchs. Viceroys are similar to Monarchs but have a distinctive flight pattern, more erratic than the smooth glide of the monarch. Viceroys also have a additional black stripe across the hind wings. Even though the adults look similar to Monarchs, you will have no trouble distinguishing the viceroy and monarch caterpillars.
Amelanchiers are small trees, large shrubs that usually grow to about 25 feet. Most are multi-stemmed. Their delicate white flowers in spring are followed by small reddish purple fruits in summer. The fruits are enjoyed by birds, but if you can get to them first, you will love them!
There are several species of serviceberry that are wonderful small trees for a suburban home. They do fine in clay soil and prefer sun to part sun.
Red Spotted Purple” (CC BY-ND 2.0) by DrPhotoMoto Red-spotted admiral (Limenitis arthemis)” (CC BY 2.0) by acryptozoo (The larval form)
Prunus americana (American Plum)
This tree is both a nectar plant for adult butterflies, and a host plant for the larvae. You will see any number of adult butterflies nectaring on it. Coral Hairstreak, Eastern Tiger Swallowtail, Red-Spotted Purple, Spring/Summer Azures, and Viceroy butterfly larvae depend on it for survival.
This is a small tree, growing 10 to 20 feet tall and about as wide. It can form a suckering colony. You can train it is a single trunk tree by trimming suckers. It is easily grown in average, dry to medium, well-drained soils in full sun to part shade. The fruit can be used in jams, jellies, and preserves. This adaptable species brings a powerhouse of ecological function to your landscape, supporting pollinators, bees, butterflies, birds. The thick branching provides shelter for birds and small wildlife.
Flowers and fruit of Prunus americana. Fruit photo: 20121003-FS-UNK-0056” (CC BY 2.0) by USDAgov
“Coral Hairstreak – Satyrium titus, Occoq” (CC BY 2.0) by Judy Gallagher One of many butterflies that utilize Prunus americana.
Asimina triloba PawPaw
The pawpaw tree is fascinating — it’s large leaves lead many to believe it is tropical. But it is indeed native to the mid-atlantic states. Commonly found in rich woods and bottomlands. Equally fascinating is the fact that it evolved before bees and other complex insects. So it depends on beetles and flies for pollination.
Its flowers are a unique maroon-ish structure. The fruit tastes somewhat like a ripe banana, and is custard-like in texture. Seedlings do best if protected from strong sunlight, so some people actually erect small tents or umbrellas over young trees. For best fruit set, two genetically different (ie, grown by seed) plants are needed. The pawpaw can form a colony and it is tempting to dig up suckers and replant. If you do this, remember suckers are genetically identical to the original tree and will not aid in cross-pollination.
Plant your pawpaw in light shade to sun with moist fertile soil. It will reach 8 to 25 feet in height and will become a beautiful pyramidal tree.
Unlike other trees, pawpaws don’t support an array of butterflies. But they are the only host plant for the Zebra swallowtail. Without the Pawpaw, the Zebra swallowtail can not survive.
No matter which tree you choose to plant for butterflies in your landscape, you can be sure you are helping out the ecosystem in multiple ways. After you’ve planted the tree, grab a field guide to insects and one for birds. Watch who visits, look them up, and enjoy observing the important role the tree plays.