Botanical and Common Name: Crocus plants have two different botanical names associated with them – Spring Crocuses are Crocus spp. And Fall Crocuses are Colchicums. To make it even more confusing some crocus varieties also have fall blooms.
Plant Category: Crocus plants are flowering bulbs that are considered perennial because they live year to year.
Bloom Time and Color: Most plants in the Crocus family bloom early spring and Colchicums, known as the 'Showy Autumn Crocus', bloom in the fall. Crocus flowers are goblet shaped and tend to be vibrantly colored in shades of yellow, purple and white with be-color accents.
Foliage: Crocus foliage appears with the flowers or, in the case of fall blooming crocuses, after the bloom season, and is an attractive green, grass-like foliage. The gardener must be sure that crocus foliage has yellowed and withered completely before cutting it so the bulb will be able to store enough energy for blooms next year.
Growth Habit: Crocus plants are upright growing flowers suited for small spaces or under planting larger perennials and shrubs.
Dimensions: Most crocus are 4-8” tall but some dwarf varieties are as tiny as 2” tall while the 'Giant Dutch' can grow as tall as 12”.
Preferred Conditions: Crocuses are hardy zones 3-9. They prefer full sun or light (dappled) shade and need well-drained soil to prevent rotting of the bulb.
Maintenance: Crocus bulbs are easy to grow and require very little maintenance if they are provided enough sunlight and well-drained soil. If your crocus bulbs stop blooming well after a couple years you may need to dig them up and divide them to encourage full blooms. The best time to divide your crocus plants would be just as the foliage has completely yellowed and died.
Pests or Diseases: Crocus bulbs have very few disease or pest problems as long as you purchase healthy bulbs without soft or rotting spots. However, squirrels are fond of newly planting crocuses and will sometimes dig them up and eat them. You can protect your bulbs buy planting them under a wire mesh (make sure the openings are large enough for the plant to grow through) like chicken wire, or dog kennel paneling.
Propagation Methods: Bulbs can be purchased and planted in the late summer through late fall for spring blooming Crocuses but should be planted late summer for fall blooming crocuses. Be sure to select crocus bulbs that are firm to the touch and don't show signs of sprouting yet. New plants can also be obtained through division.
Companion Plants: Crocus bulbs do well with other spring blooming bulbs and can easily be layered with other bulbs to create dramatic accents of color. Consider planting between larger perennial plants to provide color and interest before the foliage of the perennial plant takes center stage. Crocus plants also do well planted under deciduous shrubs and spring blooming or summer blooming shrubs.
Seasons of Interest: Crocus bulbs provide a single season of color, either in the spring or the fall, but their cheerful colors and ability to be tucked into corners of the garden that need a lift make them popular choices.
Uses in the Garden: Use crocus bulbs for spring flower beds, mixed borders, with other miniature flowers for rock gardens, for layered bulb arrangements in containers or between perennials, and to provide color under deciduous shrubs and trees.
Crocus vernus – The most popular spring blooming crocus these corms produce 6” flowers each spring that go dormant by late spring.