Crocus Varieties

Snow Crocuses

• Native to southeastern Europe and Turkey, snow crocus (C. chrysanthus) tolerates winters to U.S. Department of Agriculture plant hardiness zone 3, where winter temperatures can plunge to minus 40 degrees. Standing 2 to 4 inches high and wide, snow crocus emerges from the ground in late winter or very early spring, often appearing with snowdrop (Galanthus) blossoms. Each bulb produces up to 4 lemon- or orange-yellow flowers. Outer petals of the closed blooms exhibit purple striping. Species plants have delicate, grayish-green grasslike leaves. The slightly larger, 4-to-6-inch Advance snow crocus cultivar has orange-anthered, lemon-yellow flowers.

Spring Crocuses

• Spring crocus (C. vernus), hailing from Eastern Europe and western Russia, has become one of the most commonly grown ornamental spring bulbs. Four- to 6-inch species plants brighten early spring gardens with purple or purple-and-white, cupped flowers. The blooms unfurl on sunny days and close at night. The dozens of spring crocus cultivars include Remembrance, dating to 1925. Each Remembrance bulb produces several silvery-tinged, purple blossoms over a three-week period. Jeanne d'Arc pairs striking, purple-throated, orange-anthered white blooms with white-striped, grass-green foliage. Deep lilac stripes adorn Pickwick's silver-sheened lilac petals. Spring crocus and its cultivars tolerate winters to USDA zone 3.

Autumn Crocuses

• Nearly 50 Crocus varieties, including the saffron crocus, flower in autumn. Each C. goulimyi bulb produces a 2-to 5-inch high plant with one or two lilac-purple flowers. The fragrant blooms emerge in early to midfall, simultaneously with the bulb's green foliage. Crocus niveus, from southern Greece, has white-to-light-lilac, six-petaled flowers. The blooms' dense red-orange stamens complement their yellow throats. Both fall-flowering varieties survive winters temperatures to USDA zone 5 and 10 below zero.

Growing Crocuses

• Crocuses perform best in a sunny location with well-drained, sandy or loamy soil. These plants not only tolerate cold winters; winter- and spring-flowering varieties planted in fall require cold to trigger their bloom cycles. Fall crocuses from temperate regions flower from summer-planted bulbs. Their blooms emerge as soon as temperatures begin to cool in autumn. These small ornamentals display best massed in larger areas or in small numbers in rock gardens and other confined spaces. Spring crocus hybrids colonize over time.