WHO IS THAT WILD CREATURE Photos and words by Gale Giorgi

This article originally appeared in the Summer 2026 Napa Valley Chapter CNPS newsletter.

We had a record number of spiky red and black caterpillars in the garden this year, the larva stage of the beautiful, large, blueblack Pipevine Swallowtail Butterfly.

The caterpillars were concentrated on the Dutchman’s Pipevine, which is the only plant they will eat. Like the larvae of the Monarch Butterfly, they have evolved eating just one kind of plant. Because this plant is toxic to most other creatures, including humans, there is little competition for their leaves. This survival tactic works well until the wild habitat for this particular plant diminishes causing the population of the butterfly to also diminish.

We have two major colonies of Dutchman’s Pipevine growing in the Martha Walker Native Habitat Garden: one on the fence on the west side of the garden and one between the Children’s Garden and the Redwood Grove. The growing caterpillars stripped the vines of their leaves on the fence. The leaves on the vines by the Redwood Grove looked like Swiss cheese. This is part of the fun! We were delighted to have so many charismatic, hungry caterpillars and showed them to all our visitors. It was like having tigers at a wild animal park.

When the caterpillars reach full size, they crawl at top speed away from their host plant finding a safe place to form a chrysalis. We discovered two chrysalises resembling curled brown leaves attached to the shade structure near the fence.

If you have a shady, cool location in your yard for a Dutchman’s Pipevine, you can enjoy this miracle of nature in your own garden and help replace lost habitat that supports the Pipevine Swallowtail Butterfly.