The 16th annual “open gardens celebration” takes place June 23, 2013, at Hallberg Butterfly Gardens, 8687 Oak Grove Avenue, Sebastopol, California (map).

Hidden among the apple orchards of Western Sonoma County, the gardens cover nine acres of overgrown vines and thickets, flowering pathways and meadows.

Hours on June 23 are 10 a.m. to 4 p.m.; admission is free and no reservations are necessary. This is a great time to see the gardens, which are only open for guided tours by appointment from April 1 through October 31 each year.

The beginnings of what maybe the oldest butterfly garden in the country can be traced to the 1920s when Della Hallberg, an avid gardener, planted a California native vine called Aristolochia californica. These plantings of the Dutchman’s Pipe would provide an abundance of larval plant food for the beautiful black and teal Pipevine Swallowtail.

Today, her daughter Louise still lives in the family home and has enhanced the original gardens to provide habitat and food for over 40 butterfly species.

(Photo courtesy of Hallberg Butterfly Gardens)