Gerald L. Klingaman
Plant Common Name
Showy-flowered "bulbs" that are often overlooked because they mostly bloom late in the year rather than in spring, colchicums make excellent additions to the garden. They occur naturally from western Europe to central Asia and the Himalayas.
Colchicums produce goblet- or funnel-shaped flowers on ankle- to shin-high, stem-like floral tubes. Superficially resembling crocus flowers (leading to the misleading common name "autumn crocus"), they are typically produced in late summer or early fall, although some small colchicums bloom in late winter and early spring. Most have lilac or purple flowers, but a few have white blooms and one has yellow. The flowers often have contrasting checkering or eye zones. Large colchicums are comparable to tulips in flower size; smaller ones have crocus-sized blossoms.
Although predominately fall-blooming, most colchicums bear their lance-shaped leaves in spring. The leaves of some can reach impressive proportions. The foliage and bulbs grow from a bulb-like storage organ know as a corm, which is usually cone-shaped. Large colchicums can have corms the size of tennis balls.
Comprising hundreds of species and cultivars, colchicums are most often represented in gardens by cultivars and hybrids of two fall-blooming species: the large, rosy-purple-flowered Colchicum speciosum and the smaller, more lilac-toned C. autumnale.
Colchicums do best in full to partial sun and deep, moist, fertile, well-drained soil. The corms are often planted under low groundcovers like creeping juniper or ivy, which provide a green background and support the blossoms during wind and rainfall. These lovely perennials also are perfect for bringing new life to the late-season perennial garden or shrub planting. The corms will bloom even if not in soil! Purchase the corms in mid- to late summer, so they can be planted before they bloom.
All parts of Colchicum plants contain the potent alkaloid colchicine; see http://www.ces.ncsu.edu/depts/hort/consumer/poison/Colchau.htm
2a, 2b, 3a, 3b, 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Bulb or Corm or Tuber
Full Sun, Partial Sun
3"-7" / 7.6cm - 17.8cm
3"-10" / 7.6cm - 25.4cm
Early Spring, Late Summer, Early Fall, Fall, Late Fall, Winter, Late Winter
Europe, Turkey, Central Asia, Western Asia
Spring, Fall, Winter
Alpine, Container, Cutflower, Foundation, Lawns and Turf, Mixed Border, Rock Garden / Wall, Wildflower
Sharp or Has Thorns