Attract Black Swallowtail Butterflies to Your Yard
Fill your herb garden with black swallowtail butterflies. Learn what the caterpillar, eggs and adult butterflies look like.
Black Swallowtail Butterfly Facts
- Common name: Black swallowtail butterfly
- Wingspan: 2 3/4 to 3 1/4 inches
- Distinctive Markings: Primarily black from above, males have an extra band of yellow dots. Their bodies are also black with rows of yellow dots. On hindwings, blue markings and black-centered orange eyespots
- Habitat: Open areas such as gardens or wetlands
- Caterpillar: Bright green with black bands and yellow or orange dots. The youngest caterpillars are nearly all black with a white back patch and orange spots
- Host Plants: Celery, dill, parsley, sweet fennel and caraway
- Backyard Favorites: Adults sip nectar from red clover, zinnia and thistle
“A black swallowtail (above) 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 Birds & Blooms reader Nancy Melton.
Meet 6 common swallowtail butterflies you should know.
Eggs and Host Plants
I saw my first 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 celery, sweet fennel, caraway, parsley and dill, along with common roadside wildflowers like Queen Anne’s lace. This is one of the 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 yellow orbs, very easy to spot on the herb leaves.
Discover fascinating swallowtail butterfly facts.
Black Swallowtail Caterpillars
The eggs hatch into tiny black caterpillars with a white stripe across the middle. As they grow, the caterpillars become mostly green with black bands and yellow markings. Some people call them parsley caterpillars.
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.
Here’s how to plant a caterpillar cafe in your butterfly garden.
Where to Find Black Swallowtail Butterflies
Black swallowtails are found throughout much of the U.S., including east of the Rocky Mountains and parts of the Southwest. They closely resemble a 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 summer heat. Try keeping the herbs in partial shade and watering frequently to keep them alive and encourage black swallowtails to visit.
“This bold black butterfly (above) felt special to me because it was one of the first I spotted that spring,” says Birds & Blooms reader Linda Carissimi. “I like how the swallowtail posed with its wings open on the clematis.”