This spring, I’ve been getting some interesting questions as more and more homeowners are enjoying their landscapes and gardens. Lots of these questions are about the various caterpillars we find also enjoying our landscapes and gardens.

The questions arise because, since we have caterpillars, we have plants being munched on.

There are the bad actors, like the big tomato hornworms, which seem to devour an entire tomato plant in a single night. Another bad one is the yellow-striped armyworm that sets up camp in the tomato patch.

I recently posted a “Daily Dose of Hort” video on these guys and how to control them. You can check out videos from this series and other useful garden and landscape information at the Southern Gardening Facebook page,

But we also have voracious caterpillars that transform into beautiful Swallowtail butterflies.

Many home gardeners intentionally grow the forage plants these caterpillars need as a food source. However, new gardeners often are horrified when they find caterpillars consuming their lone herb plant, and they ask me how to control them.

The commonly seen Eastern black swallowtail caterpillars are large — about the size of a little finger — and striped in black, yellow and green bands with yellow spots. They are attracted to dill and parsley.

The developing caterpillars are small and usually dark in color with a wide, light-colored saddle across the middle. I’m always careful after harvesting herbs to look for the small caterpillars. I return those I find and place them on the dill or parsley.

A favorite dill that I plant in my home landscape is an improved selection called Bouquet. This dill flowers early and often, and we harvest the large umbels for use in making dill pickles.

It doesn’t matter what parsley I grow; I enjoy them all, as do swallowtail caterpillars.

The giant swallowtails use citrus, mainly satsuma and Meyer lemon, as forage. These caterpillars are commonly called orange dogs or bird-dropping caterpillars. Their bird-dropping mimicry is a defense against predators. Young caterpillars are found in plain view in areas where bird droppings would be expected, hence their very descriptive common name.

I enjoy watching these guys munch on the leaves of my satsuma and Meyer lemon trees as they grow. When I see these caterpillars, I leave them alone, as there’s no danger of them munching all the citrus trees' leaves.

So, my advice when you have these caterpillars is always to just plant more and share with the swallowtail caterpillar. You will be rewarded with beautiful swallowtail butterflies.

• Dr. Gary Bachman is an Extension and research professor of horticulture at the Mississippi State University Coastal Research and Extension Center in Biloxi. He is also the host of the popular Southern Gardening television and radio programs. Contact him at

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