What Happened To My Colchicum?

Do the leaves and stems of your colchicum have brown spots on them?

Does the whole plant look stunted and yellow, roots have lesions on them?

Is the foliage distorted, flowers are absent, and the corms are rotted?

Do the leaves have large, ragged holes in them?

Do the leaves have soothlike masses, that break up into a black powder when you touch them?

Are the flowers covered with gray mold, leaves may be blotched or discolored?

Brown spots on leaves and stems of colchicum are caused by frost injury. Colchicum leaves is often caught by late spring frosts. Small brown spots later merge into blotches. They sometimes split and look ragged. Prevent frost injury by laying down a mulch layer over the corms right after the ground freezes in the fall.

Stunted and yellowed plants with roots that have lesions on them are caused by Bulb Nematodes. Bulb nematodes are microscopic, wormlike creatures that attack bulbs. To prevent nematodes mulch regularly with compost to ensure that soil organic matter levels remain high. Heavily infested plants can only be removed and replaced with some other plant species.

Likely cause for these symptoms are insects - Bulb mites. These, almost microscopic insects feed on plants' corms and bulbs. Severely infested corms should be dug up and destroyed. Don't replant corms in infested soil. To destroy bulb mites in infested corms, dip them into 120°F hot water for a few minutes.

Large, ragged holes in the leaves are caused by slugs and snails. Slugs and snails feed on the plant leaves usually at night. To control slugs and snails use diatomaceous earth around your plants. You can also handpick them during the night or use shallow dishes filled with beer as a trap.

Fungal smut is a plant disease that is known to infect colchicums. If the infection is mild, cut off and destroy all infected leaves. In more severe infections all you can do is destroy plants to stop smut from spreading.

Gray mold on flowers is probably caused by fungal disease - Botrytis blight. You can only prevent Botrytis blight disease by planting flowers in areas with good air circulation. Water plants sparsely. Infected plants should be removed. Spray weekly with a copper fungicide until the disease is under control.

If the plant has disappeared and the corms are missing the culprits are animal pests. Rodents such as mice, voles, squirrels, and gophers will eat corms and can quickly make a planting disappear. The presence of a pet dog or cat often deters rodents. Line planting beds with screen or hardware cloth to keep pests from burrowing around corms. Lay one-inch wire mesh over bulb beds and fasten it to the soil with pegs to discourage squirrels and chipmunks from digging up corms.