Range: Most extensive of all Californicae: a narrow coastal band extending 700 miles between central Oregon and Santa Barbara, California.
Original material: Monterey region, coast of central California, by David Douglas 1830?
Key identifying features:
Flower color: Usually shades of light blue-violet to dark purple; occasionally white, rarely yellow.
Habitat: Grows naturally along coastal zones, usually within sight of the ocean and common on bluffs and treeless grassy hillsides. It sometimes extends farther inland in areas where human activity has opened forests to abundant sunlight. Unpalatable to livestock; some ranchers consider it an aggressive weed.
Name: By Rev. George Herbert, after the naturalist David Douglas, who collected the original specimens.
Comments: This is a vigorous, highly successful iris, common and widespread in coastal areas. It readily crosses with each of the other PCNIs where their ranges overlap.
When Douglas iris is found farther inland, it is usually because it has crossed with other local iris species, better adapted to less exposed, shady habitats. If you know the local iris, you can often see evidence of this genetic mixing.
Some long established natural hybrid populations have been given their own names, like the colorful "Marin Iris" and "Santa Cruz Iris" (douglasiana × fernaldii × macrosiphon) in the Coastal Range just north and south, respectively, of San Francisco's Golden Gate, and "Thompson's iris" (innominata x douglasiana) along the California/Oregon border.
Douglas iris is widely used in the nursery trade, both as the species, and as a parent stock for many successful hybrids. In some way, it is involved in nearly all the named PCI horticultural varieties. Most are man-made hybrids - crosses from specially selected parents, but some are pure, wild plants grown because of certain outstanding features.
Some of the more successful strains of pure Iris douglasiana include "Amiguita" - blue bi-tone with a purple signal spot; "Canyon Snow" - white with yellow eyespots; "Harland Hand" - purple, with a long blooming season; and "Mendocino Banner" - white with purple veins and contrasting purple style crests.