By Jim McCausland, Sunset senior garden writer
Autumn crocus (Colchicum autumnale) just seems to have things backwards. Its leaves emerge as winter begins, but vanish at the beginning of summer (the foliage in the picture below belongs to a nearby daylily); and its fragrant flowers appear on leafless stalks at summer’s end, dying without a trace three weeks later.
But maybe that’s why I like this plant: by being out of sync with everything else, it's good at filling gaps in my garden’s foliage and flower cycles.
You grow these from bulb-like corms sold now. When you shop, you’ll probably find some corms sprouting (maybe even blooming) in the bin.
Try to choose unsprouted corms, but if you have no choice, even the sprouted ones are o.k.: just get them into the ground as quickly as possible. Fortunately, you only have to buy once: corms multiply fast enough that within a few years you’ll have plenty to give away.
My autumn crocuses are single pink ones, but you can also find white and purple-lilac forms, and double-flowered versions.
Though these are called crocuses because the flowers look similar, autumn crocuses are really quite different. Spring-flowering crocuses are in the iris family, have late-winter bloom, and grassy foliage. Autumn crocuses are in the lily family, bloom in late summer, and have 20-inch-long, 1 1/2-inch wide leaves.
Autumn crocuses contain a fascinating, poisonous akaloid called colchicine. It is toxic enough to kill you, so don't ingest any part of the plant. But it also has pharmacological value in the treatment of cancer and other ailments, and it is used to intentionally cause beneficial mutations in plants. Seedless watermelons, for example, were derived from work with colchicine.
Try a few bulbs in a circle around the base of a deciduous tree. I grow mine under a Japanese maple, where they'll soon be making a pool of pink flowers. In the dead of winter, enough sunlight will filter through the leafless tree branches above to give autumn crocus leaves all the sunlight they need to produce another crop of flowers next year.
Autumn crocus grows in Sunset climate zones 2-10 and 14-24 (that's everywhere except coldest mountain regions and low and intermediate desert).
