Let it Grow, Let it Grow
Traditionally when growing herbs we worry about bolting, harvesting for peak flavor, pruning. No need to fuss with that! Let your herbs grow wild, let them flower! Butterflies and other pollinators will love it, and the caterpillars will do the harvesting for you. Annuals can be seeded in succession every 2-3 weeks. Rue, Parsley, Cilantro, Dill, and Fennel are host plants for the Black Swallowtail butterfly. Rue is also the host plant for the Giant Swallowtail butterfly.
No Pesticides
Insecticide and herbicide applied near or around your butterfly herb garden is harmful to your caterpillars and butterflies. Use caution when applying pesticides around your herbs.
Look for Eggs
Look for eggs in late spring, early summer and into fall. Look for single eggs throughout plant. Butterflies do not lay mass clusters of eggs. During the hottest periods of the summer, you may see less activity.
Know Your Caterpillars
Black Swallowtail caterpillars are often mistaken for Monarch caterpillars. You will never find a monarch caterpillar on your herbs (their host plant is milkweed). The caterpillars also look very different at each of their larval stages. Monarch caterpillars have two pairs of antennae-like tentacles, one pair at each end of the body. Swallowtail caterpillars do not have tentacles.
Black Swallowtail
Giant Swallowtail
Stranger Danger
Wasps, birds, lizards…they all go after caterpillars. One day you may have several young caterpillars and the next they could be gone. Blame it on the food chain. If you are interested in protecting your caterpillars you can loosely drape a fine mesh plant cover over the entire plant (keeping the bottom open for caterpillars to crawl out when they are ready).
Chrysalis Hide and Seek
It can be hard to find a chrysalis. Caterpillars often wander away from their food source, find a protected area and form a chrysalis. You may luck out and a caterpillar will form a chrysalis under your patio table or on a stem of your herbs. Be sure to leave your herbs alone. The caterpillars need this time to transform.
Know Your Butterflies
Butterflies have different patterns on their dorsal (visible when wings are open) and ventral (visible when wings are closed) sides.
Thank Your Herbs
Your herbs may look pretty beat down by the end of the season. Heat will eventually take out cilantro and parsley, but they did their job and provided a food source. Dill hangs in there a bit longer, and rue and fennel are perennials so they should be fine. If a caterpillar eats your herbs to the ground, great! That’s the job of a host plant!