Douglas irises are great foundational plants for a partly sunny or partly shady area of your garden. Their foliage is green all year round, and when in bloom in the spring, they create a welcome spot of color in shaded areas.
Douglas iris (Iris douglasiana) is native to coastal areas from Santa Barbara into Oregon, growing in full sun along the immediate coast but also in the light shade of open woods and forest edges. I have several different forms in an area of my El Cerrito front garden that gets a small amount of filtered sun in the early morning but is in bright shade most of the day. Apparently they bloom less in deep shade, but my Douglas irises bloom faithfully every spring. Last fall I divided some clumps and spread them out, so now they are starting to really fill out that garden bed. They are decent at outcompeting most weeds, including Bermuda buttercup (Oxalis pes-caprae). A few weeds grow through the iris foliage, but that’s nothing compared to the number that would be there without the irises, and the weeds are easy to spot and pull.
Douglas iris flowers in the wild have a wide range of colors from white or pale yellow to light blue to dark blue to lavender and deep purple. On a recent early April trip to Point Reyes National Seashore, I saw several Douglas irises in bloom, and even in one small area there were distinct color differences.
I have grown Douglas irises from seed, and they have generally been a deep blue-purple. They are easy to grow from seed, and they usually bloom the second year after germination. Because the seeds will have varied genetics, the result may be many different shades of blooms. My seed source is Larner Seeds in Bolinas, If you want quicker gratification, you can find full-grown Douglas iris plants in stock at our CNPS East Bay Chapter’s Native Here Nursery in Tilden Regional Park.
I have also bought some interesting Pacific coast iris cultivars that are still going strong many years later, including blue and white ’Fancy Pants’ and creamy yellow ’Banana Cream Pie’. Both of these cultivars were bred from native irises by Ryan Grisso for Annie’s Annuals in Richmond, which is where I purchased them years ago. Unfortunately they have both been discontinued at Annie’s. Cultivars are a wonderful addition to the more “wild” forms in my Douglas iris bed.
Depending on where they’re growing, Douglas irises require very little, if any, summer water, and I water mine very infrequently in the summer. However, since we have had so little rain, I have given them some supplemental water this spring (approximately once a week), and they are blooming like crazy now in mid-April. In more sun or in warmer areas, they benefit from occasional watering during the dry season.
CNPS’s horticultural website Calscape says Douglas iris prefers heavy soils with organic matter. My garden definitely falls into the heavy clay soil category, although without much additional organic matter except decomposing leaf litter, and the irises are thriving. With heavy soil, the recommendation is to be careful not to overwater the plants.
I recommend Douglas iris as a wonderful long-lived evergreen perennial that serves nicely as a border plant or in a lightly shaded area of your garden.
— Robin Mitchell, Recording Secretary, CNPS East Bay Chapter