California poppy, sky lupine and many favorite coastal wildflowers are annuals. Douglas iris, Iris douglasiana, blooms with the best of them as a perennial. It is persistent enough to be a noxious weed within rangelands. Of course, that is only because it competes with forageable vegetation. Douglas iris is actually tame enough for cultivated home gardens.

Douglas iris bloom is mostly the color of faded blue denim. It can alternatively be slightly richer lavender blue or very pale bluish white. Purple with yellow centers is rare. Flowers stand only about a foot to a foot and a half tall. Their deep green foliage is about as high. Individual leaves are narrow and arching. New leaves displace deteriorating old leaves.

Wild Douglas iris colonies can be impressively expansive. They generally mingle nicely with other low vegetation and wildflowers. With occasional irrigation, they can get dense enough to exclude most other vegetation. However, such colonies are not evenly dense, so develop bare zones. They crave good sun exposure, but tolerate a slight bit of shade. Excessive fertilizer might inhibit bloom. Excessively frequent or generous irrigation might cause rot.