Culture

Colchicum Culture:

Gardener difficulty rating for genus: 2
yellow-thumb special - easy to grow in right condition

Habitat : Colchicums are native to hillsides, grasslands, scrub, and open woodlands of north Africa, Europe, and central Asia.  

Hardiness :   Its range extends from Zone 4 to 8.  

Light : Full sun to part shade.   Colchicums in deep shade bloom poorly.

Soil and pH : Autumn crocus, like most bulbous plants, requires well-drained soil.    Garden pH is not as important as rich, fertile soil for luxuriant growth and flowering.

Moisture : Colchicums require little watering.   They are inactive during Summer when evapotranspiration is highest.   If Spring or Autumn are severely dry, supplemental watering will help.  

Planting : They are normally sold as dormant bulbs in late Summer.   Wear gloves to avoid the toxin, colchicine.

Plant 4-6" deep in well-drained, fertile soil.  

Interestingly, the bulbs do not need to be planted to bloom.   Bulbs bought in early Autumn can be placed in a sunny spot and "forced" to bloom.    This is a neat property but ,like all forcing, it severely drains the bulb's life force.

Pruning : Wait to remove withering foliage until it yellows completely.   Super-tidy gardeners can trim away ugly sections of leaves as they fade to avoid a prolonged mess.  

Pests and Diseases : The toxic chemical colchicine protects autumn crocus from most pests.   No deer, rabbit, vole, squirrel, grasshopper, or even cow will eat them.   Slugs and snails are the only creatures virulent enough to feed upon the leaves and (more distressing) the flowers.

Propagation : Propagation is possible through division or seeding.   Large colchicums produce smaller offshoot corms every year.   The best time to divide is early Summer as the leaves are withering.   The bulbs are easy to find when the leaves are still present.   In late Summer finding the dormant plants can be tricky.   Simply lift the corms and cormels (little corms) then replant in the desired area.

Harvesting seed is trickier.   First, the flowers must be pollinated either naturally or by hand, and marked.   Then the seeds must ripen throughout Winter.   Finally the seeds must be found and collected in late Spring.   That is too much planning for all but the most meticulous gardener.   Most of us are not thinking about colchicums in Spring when daffodils, trilliums, and anemones demand our attention.   After ten years of growing a variety of colchicums, I am not sure if I have ever even seen a mature seedpod.   However, they do exist.   Like most bulbous monocotyledons, from seed to flowering takes between 4 and 7 years.

Gardeners looking a fall accent should plant autumn crocus.   Their cheerful blossoms bring color and warmth to the cool autumn days.