The Pipevine Swallowtail butterfly and its host plant
Photo by Tim Wong (@timtast1c)
The beautiful blue Pipevine Swallowtail Battus philenor is rarely sighted these days here in Northern California because there isn't enough of its only host plant, the California native pipevine, California Dutchman's-pipe, or California snakeroot to be found.
However there is a movement among local pollinator groups, of which I am a member, to plant more of the Dutchman's-pipe in gardens. Since this plant isn't offered for sale in local plant nurseries, one has to be lucky to know someone who propagates the plants from cuttings from the vines.
Here is the link to a wonderful video about the Pipevine Swallowtail and its host plant: