Culture
Best grown in organically rich, medium moisture, well-drained soils in full sun to part shade. Sharp soil drainage helps prevent corm rot. Purchase dormant corms in late summer (August) and plant them immediately (3” deep and 6” apart) for bloom in fall. Dig and divide corms when plants become crowded (every 3 years). Site corms in areas where the short flowers may be enjoyed in fall but where the taller spring foliage will not interfere with other perennials. Reduce watering when the foliage yellows and begins to die back (July). Resume watering again in late summer.
Noteworthy Characteristics
Colchicum autumnale, commonly called autumn crocus or meadow saffron, is a cormous perennial that typically blooms in early fall. Plants send up only foliage (5-8 lanceolate dark green leaves to 10" long) in spring. Foliage gradually yellows and dies by early summer when the plants go dormant. Naked flower stems (1-6 stems per sheath) rise from the ground to 6-10” tall in late summer to early fall, each stem bearing a star-shaped, lavender-pink to lilac-pink flower. Fall flowers have no foliage, hence the sometimes used additional common name of naked ladies for this plant. Medicinal colchicum and colchicine come from the corms and seeds. The common name of autumn crocus is somewhat misleading because autumn crocus (Colchicaceae family but formerly included in Liliaceae family) is not closely related to spring crocus (Iridaceae family). Among the differences, the flowers of autumn crocus have six stamens and the flowers of spring crocus have three stamens.
Genus name come from the abundance of the plant in Colchis, the Black Sea region of Georgia, Caucasus.
Specific epithet refers to autumn when this plant flowers.
‘Pleniflorum’ features rose-pink double flowers. ‘Pleniflorum’ is synonymous with ‘Plenum’ and ‘Roseum Plenum’.
Problems
No serious insect or disease problems. Watch for slugs and snails. Fungal smut may attack the leaves (remove and destroy affected plants). Weak flower stems tend to flop.
Uses
Meadows, woodlands beds. Good for pockets in the landscape where spring and summer plants are fading. Good around patios or along walks. Plant with low ground covers which may help support weak flower stems. Generally inappropriate for prominent parts of beds or borders because of the unsightly appearance of the spring foliage as it yellows and declines on its way toward summer dormancy.