Autumn crocuses (Colchicum), bulbous perennial plants that flower in fall, are a strange breed. The genus has been referred to as Filis ante Patrem (''the son before the father'') because, unlike most plants' growth cycle, the flowers, which actually grow from corms, appear before the foliage.
Like spring-blooming bulbs, the blossoms are beautiful -- large with soft, elongated petals in a wide range of colors such as yellow, fuchsia, and soft lilac -- and the plants are easy to cultivate, able to thrive in flower beds, borders, and rock gardens, as well as on windowsills. Because colchicums are toxic, they provide a natural way to repel animals such as deer, mice, squirrels, and moles.
When selecting colchicum corms, look for ones that are firm, dense, and heavy.
Plant them in late summer or early fall in well-draining, compost-amended soil, 4 to 6 inches deep and 6 to 9 inches apart. Use a tool called a naturalizing bulb planter, which is designed to break through hard soil, with which to plant.
Although shade tolerant, they prefer full sun. The corms can be planted if they're in bloom, just be careful about where you place them; the colchicum's large, floppy foliage, which does not emerge until spring, could shade out small plants if they're growing nearby.
When in growth, water the plants moderately, and avoid wetting the foliage and flowers; keep them dry when dormant.