How to store dahlias and other tender bulbs.

 

Summer flowering tropicals, such as begonias, cannas, dahlias and gladiolus are considered tender bulbs in our climate. They won’t survive our winter, if you leave them in the ground. Some gardeners choose to treat these summer flowering favorites as annuals and plant new bulbs every year. Another choice is to dig up each bulb and store them until its warm enough to plant next spring. Here are some things to do if you decide to store your bulbs.  Note: the word "bulb" is being used as a generic term for dahlia tubers, gladiolus corms, canna lily rhizomes and tuberous begonia tubers.

After first frost, when the leaves turn black, is the time to dig tender bulbs.

Cut the remaining foliage back to about 5"-6". You can cut the foliage back before you dig the bulbs or afterwards, whichever is convenient.

Raise your bulbs with a spading fork, digging carefully to avoid damage to the bulb.   

Rinse each bulb off to remove excess soil then let dry in a shady spot.

After the bulbs dry, dust each one with sulfur. Sulfur will help ward off diseases and insects.

Remember to label each bulb going into storage. Write directly on the bulb with a Sharpie or use plant labels. Bulbs can be stored in cardboard boxes or paper bag containers layered with peat moss, vermiculite or shredded paper. The packaged bulbs should be placed in a dark, cool location. Choose a spot where the temperature will stay between 40º and 50º.  The packing material will help stabilize the temperature.   Bulbs need attention during storage, so check on them every week or so. Make sure they don’t dry out and keep an eye out for damage or disease that may show up in storage. If the bulbs look like they are shriveling up, mist the packing material to add moisture. 

Your bulbs may have increased in size during the growing season. Wait until spring to divide dahlias and cannas.

Each gladiolus corm will have a number of baby corms, known as cormels or cormlets attached to the bottom. Save these and plant them next season. They will grow into flowering size in a couple of years.