Satin Flower (Sisyrinchium douglasii)

This text was originally published in Coastal Grower (formerly The Island Grower) in Victoria, British Columbia. For subscription information, please call Susanne Steele at the Coastal Grower at 250-478-0825.

The Iris Family (Iridaceae) has provided gardeners a huge selection of breathtaking ornamental flowers, among them crocuses and irises. There are few native representatives of this family in British Columbia mainly several species of blue- and golden-eyed grasses. Satin flower (a type of blue-eyed grass) is without doubt the showiest of these though probably the least known in gardens.

Satin flower grows as a low clump-forming perennial 10-30 cm (4-12") tall. Plants grow from a small mass of matted root-stems (rhizomes) , which produce tenacious true roots on the lower surface and narrow grass-like leaves and stems from the upper surface. The leaves emerge as early as January. They are somewhat flattened, pointed at the tips with basal ones rising about 10 cm (4") tall. Prominent parallel silvery lines mark the surface. The leaf base sheaths the lower part of the stem.

Erect and pointed flower stalks look like leaves. But just below the top, buds and flowers burst out from the side of the stalk on a slender stalklets. Each 4-5 cm (1.6-2.0") wide bell consists of six royal purple tepals (undifferentiated sepals and petals), either facing outward or often hanging downward. There are two to three flowers in each cluster. Three stamens project out of the centre of the flower and surround a three-parted wispy stigma. The egg-bearing ovary swells beneath the tepals and upon maturity becomes a seed capsule. Most wild plants have purple flowers, but pink and white forms occur too.

Satin flower blooms are among the earliest of all wild flowers to appear. On south Vancouver Island you may see them as early as late February and certainly by March.

The natural range extends from south Vancouver Island to California. Satin flower sneaks through the Columbia River Gorge onto the sage lands east of the Cascade Mountains suggesting that it might be suitable for southern interior B.C. gardens. The species thrives in open settings, on south Vancouver Island, mainly in shallow mossy soil on rock knolls and meadows. In the US interior it occurs in sagebrush, pine and open oak woods. A critical feature of the habitat is wet spring soil, though the site can become totally baked in the summer.

Satin flower makes an excellent early spring garden subject for the sunny rock garden. It will grow in light deciduous shade too in normal garden soil, so you can use it at the front of a shrub border. In the dry season, plant the root clumps just below (2.5 cm=1") the surface and mulch lightly with organic matter. The plant settles in quickly but spreads slowly. Usually it blooms the first spring after planting. Satin flowers propagate easily from small rooted pieces of the matted crown. Once established they spread by seed. You can raise satin flowers by sowing mature seed in the summer and leaving it over the winter. Germination is mediocre with only 10-20 % of the seeds sprouting. Do not dig this relatively uncommon plant from the wild, rather try raising it from seed or have the local garden centre order it from a specialist nursery.

The name Sisyrinchium is apparently based on an ancient Greek name for another plant, though some experts think it may mean 'similar to iris'. The species name douglasii honours David Douglas a renowned botanical explorer of the Pacific Northwest two centuries ago.

Next time you see large and showy bearded irises think of their tiny kin the satin flower and blue- and golden-eyed grasses. These native wildlings may not be as flamboyant but they are equally delightful.

For more information on native plants, contact Richard Hebda the Royal British Columbia Museum.