Back in 2020, when I was posting stories about our Shamrock Gardens butterfly calendar, I somehow ran out of steam (it was a challenging time). Now that my Butterfly Gardening book is out, I thought I’d finish the job. October, November, December, here we come! First up: Pipevine Swallowtails.

I so love these beautiful butterflies. Like many Swallowtails, their wings mix black, blue and other colors. But Pipevine blue has an especially brilliant sheen.

A butterfly’s color comes from the structure in its wing scales – each butterfly has as many as a million of them. These scales reflect light in varying wavelengths. Macro-photographers such as Thorben Danke capture amazing pictures of them.

The structure of the scales on Pipevine Swallowtail wings bends light waves in ways that produce a shimmering effect known as iridescence. Iridescent colors change dramatically when viewed from different angles (you can see this effect in the contrast between the right and left hind wings of the Pipevine pictured below).

Pipevine Swallowtail caterpillars look like they’re dressed for Halloween.

They’re distinctive in other ways as well. Butterfly caterpillars generally lead solitary lives (moth caterpillars are often more gregarious). Most female butterflies lay one egg at a time, carefully spacing their eggs across the leaves of host plants. Pipevines lay eggs in groups. After the caterpillars emerge, they often hang out together.

As their name suggests, Pipevine caterpillars feed on Dutchman’s Pipevine – named because its flowers look like Dutch pipes. We planted a Pipevine at Shamrock, and after a few years it covered our enormous Spicebush. It took several years for the Pipevine Swallowtails to find it. But once they did, we had caterpillars in abundance.

Happy Halloween!