Attract Eastern Black Swallowtail Butterflies
Fill your herb garden and share the bounty with eastern black swallowtail butterflies. Learn what the caterpillar, eggs and butterflies look like.
Courtesy Linda Carissimi
Eastern Black Swallowtail Butterfly Eggs and Host Plants
I saw my first eastern black swallowtail butterfly the other day, and it immediately sent me running to my parsley bed to see if the butterfly had laid any eggs. You see, most people grow herbs for cooking, but I tend to grow them mostly as host plants for butterflies.
Black swallowtail butterflies (Papilio polyxenes) lay eggs on parsley, dill, fennel, and rue, along with common roadside wildflowers like Queen Anne’s lace. This is one of the very easiest butterflies to lure to your own backyard, just by planting a bed of these herbs in a sunny spot. The eggs are lovely little pale green orbs, very easy to spot on the leaves of the herbs. The eggs hatch into tiny black caterpillars with a white stripe across the middle.
Eastern Black Swallowtail Facts
- Wingspan: 3 1/8 to 4 1/2 inches.
- Distinctive Markings: Black wings with two rows of light dots. On hindwings, blue markings and black-centered orange eyespots. Bright yellow dots on abdomen.
- Habitat: Open areas, including gardens, fields, deserts and marshes.
- Caterpillar: Bright green with black bands and yellow or orange dots.
- Host Plants: Carrot, parsley, Queen Anne’s lace and dill.
- Backyard Favorites: Adults sip nectar from red clover, zinnia and thistle.
Courtesy Kathleen Potter
Eastern Black Swallowtail Caterpillar
The caterpillars of this species undergo many changes before they’re ready to pupate. These different phases are called “instars”. The process takes about two weeks from egg to chrysalis.
A black swallowtail spends the winter as a chrysalis (remember, butterflies form a chrysalis, while moths form a cocoon). It contains a chemical that acts as antifreeze so it can survive cold temps. Then it emerges as an adult come spring. And it’s always worth the wait.
“This bold black butterfly felt special to me because it was one of the first I spotted that spring,” says Linda Carissimi of Simsbury, Connecticut.
Here’s how to plant a caterpillar cafe in your butterfly garden.
Courtesy Nancy Melton
Where to Find Eastern Black Swallowtails
Eastern black swallowtail butterflies are found throughout much of the U.S., including the entire southeast. They closely resemble another common southeastern species, the spicebush swallowtail. Although they fly all summer long, in the deep south the herbs they use as host plants may struggle to grow in the sultry summer heat. Try keeping the herbs in partial shade and watering frequently to keep them alive and encourage black swallowtails to visit.
“A black swallowtail sipped nectar from a clover plant at the edge of a pond. I love the colors in this photo, along with the crisp image. It was a beautiful day to watch nature unfold,” says Nancy Melton of Camden, Tennessee. Next, discover 7 fascinating monarch butterfly facts.