These beautiful caterpillars are sometimes mistaken for the Monarch variety, but in fact they will become Black Swallowtail butterflies. Of course, that’s after they consume all the leaves off your parsley, dill, or fennel plants. (The lower photo is the same caterpillar after I touched it. The two orange tentacles pop out of their head when you do that.)
I was willing to sacrifice our potted parsley plant for the good of these little guys. After all, they will turn into striking butterflies that pollinate plants and watching the tentacles pop out of their head several times was pretty entertaining. If you’re willing to sacrifice your parsley plant, I have good news….it can regenerate. Here’s a photo of ours making a surprising comeback a couple days after the caterpillars disappeared.
To save the foliage on your plant, just remove the caterpillars. No need to spray anything. Since they only consume parsley, fennel, Queen Anne’s lace and dill, they will die without these food sources. Another option is to give them their own food source, perhaps a second plant or fresh herbs from the grocery store placed in a narrow container of water. A narrow container prevents the caterpillars from falling into the water and drowning.
As garden pests go, these are good ones. Providing a food source for butterfly caterpillars, other than the plants you want to eat, is a win-win for insect, human and the environment alike.