How are your overwintering bulbs: Dahlias, Cannas, Gladiolas, and more...?

Dahlia

If you are trying to overwinter bulbs (includes tubers, corms, and rhizomes) such as Dahlias, Tuberose, Amaryllis, Canna Lilies, Gladiolas - now is a great time to check them to see what condition they are in. Here are the main things to check:

#1 Check for Disease If bulbs are damaged in digging and not "cured" well while preparing them for storage, you can get a soft rot in them and it will spread from bulb to bulb, or tuber to tuber very fast. A fast way to check for this is to use your nose, the rot will give off a rather bad smell, once you detect the smell, then use your eyes to look for discolored material or material that is oozing and looks moist.

Remove all bulbs that show the discolored symptom or are soft, you should also check with a master gardener to see is there is a fungicide that you can treat the ones not affected to protect them.

Canna lily rhizomes

Canna Lily

 #2 If you have put the bulbs in an organic bedding material, check it for moisture content - if it is damp that could increase problems with soft rot.

#3 Check the bulbs to see if they are wrinkling up which shows that they are drying out. Outside air can become very dry when it warms up causing a severe problem in over wintering your live material. 

Tubers such as dahlias are very prone to not surviving the winter unless they are in bedding material. If the bedding material is too dry,  it can allow the bulbs to dry out and die, of course if it is too damp then soft rot can be a problem.

Gladiolus corms

#4 Check the temperature of the area you are storing them in. It should be less than 50 degrees F. and more than 40 degrees. It is very important that the bulbs do not freeze and if it gets too warm the bulb will start to grow and that can kill it.

For more information on growing flowers, contact your local University of Idaho Extension office!