Douglas Iris: Nature Notes from the P.G. Museum of Natural History

White and purple Douglas iris in the Museum’s native plant garden (photo by Annie Holdren)

White and purple Douglas iris in the Museum’s native plant garden (photo by Annie Holdren)

In the early 1830s, somewhere near Monterey, David Douglas collected the first botanical specimens of what’s now known as the Douglas iris (Iris douglasiana). This species is the most extensive of all California irises, ranging in a narrow coastal band from Santa Barbara County through central Oregon.
The Douglas iris blooms in colors ranging from pale cream to deep purple, marked with yellow and white blazes. The flowers’ color range is caused by genetic mixing (hybridization) with other iris species. Some iris hybrids have resulted from crossing naturally in the wild; many others have been hybridized in the nursery trade. 
Of course, genetic mixing occurs through the plants’ sexual reproduction. But when you see a large clump of iris, that patch probably reproduced asexually through runners (rhizomes). It’s a clone, and may be hundreds of years old.
An unusual white Douglas iris grows in the native plant garden of the Pacific Grove Museum of Natural History. According to Vern Yadon, Director Emeritus of the Museum, he collected the plant decades ago from the Del Monte Forest. A resident showed him a white iris patch growing near the end of Congress Road in a place now covered by paving. Yadon identifies this white iris as a kind of albino (known as “albiflora”), resulting from the expression of a recessive gene. Have you seen any white Douglas iris growing wild in the Del Monte Forest? The Museum would like to make note. 
If you are interested in seeing the myriad colors that all wildflowers present, don’t miss the 54th annual Wildflower Show (held April 17-19 at the Museum).