The care information provided in this section represents the kind of practical advice is available for all the plants in this web site if you subscribe to the monthly customized newsletter Yardener’s Advisor.
Colchicum, like most bulbs, require very little care. It is important to allow the leaves that appear in the spring to age and die naturally so that the corm can acquire and store energy through them for blooming in the fall.
Ideally, Colchicums should get 1 inch of water a week from rain or from your watering system. If your corms haven't gotten 1 inch of water during the week, check soil moisture under the mulch to see if you need to water. Colchicums don't need much water while they're flowering, but water regularly later to encourage rooting and help the corm store up nutrients for next season. Use a sprinkler or soaker hose for gradual penetration to a depth of 10 to 12 inches. If you can do your bulb planting just before a good soaking fall rain, you won't need to water. During hot, dry weather, water thoroughly once a week. For information on products see the file on Choosing Watering Equipment
Colchicums do best when fed twice a year, in the early fall prior to blooming and again in the early spring before their leaves appear. Sprinkle about a tablespoon of granular bulb fertilizer per plant or a small handful per cluster. Do NOT feed colchicum after flowering in the fall when the corms can least use the nutrients. This may encourage disease.
Mulching and Weed Control
A 1 or 2 inch layer of organic material such as chopped leaves, shredded bark or wood chips spread over the bulb bed as a mulch, controls weeds and conserves soil moisture. When they bloom, it prevents dirt from splashing up on the flowers. Rake fallen leaves off the bulb bed in late fall. They may mat and prevent water from reaching the bulbs during the winter. For more information see the file on Using Mulch
Each year colchicums corms produce smaller "cormlets", attached to the parent corm. They are a source of new plants. After 3 or 4 years in the ground, colchicums may grow into crowded clumps and can be divided. Dig up the corm clumps after the flowers appear in the fall. Gently shake the soil off the roots, separate the cormlets from the parent corms and discard the old shriveled parent corm. Replant the cormlets quickly to prevent roots from drying out. Cormlets bloom in 1 to 2 years.