University of Illinois Extension

Digging and Storing Summer Bulbs

Putting things away at the end of one season and bringing them back out the following season is something we all do, said Greg Stack, a U of I Extension horticulturist.

“At the end of the winter we put away our sweaters and heavy coats and bring out our shorts, light clothing and other summer attire in anticipation of those warm summer days,” said Stack. “For gardeners it’s no different when we start to think about putting away or saving our tender summer bulbs and storing them over the winter in anticipation of when we can replant and enjoy them next summer.

“If you’ve invested in cannas, tuberose begonias, dahlias, gladiolas, caladium or elephant ears, you may want to take a little time this fall to gather them up and save these bulbs for next season. It’s easier than you think and doesn’t really require any special place to do it. If you have a cool, dry, dark location you have a suitable bulb storage area.”

So, what are the best ways to store some of our summer flower bulbs and know they will be ready to go next spring?

There are no absolute rules for storing bulbs over the winter, Stack noted. But, there are some general considerations you need to be aware of and follow if you want to be successful.

“Keep the bulbs, cool, dry and above freezing; don’t store in air tight containers that might favor rot or fungus; check on them regularly for either signs of drying out or mold; don’t store bulbs in a refrigerator where ethylene gas from fruits and vegetables can damage bulbs; and remember to label by color and type of bulb,” he explained.

As far as specifics, Stack offered guidelines for some of the more popular summer flowering bulbs.

Tuberose Begonia

Allow a very light frost to kill back the tops. Dig the tubers from the garden or pot and set them in a shaded, cool area to dry for about a week leaving about five inches of the stem still attached. After a week of drying lightly brush away any loose soil and the top should separate easily from the tuber. Store them in trays filled with peat moss or sawdust in an area that is dark, well ventilated and about 50 degrees F.

Caladium

Dig caladium before a frost and put them in a cool, dark, well ventilated area to allow foliage to dry. Cut back the foliage and pack the tubers loosely in peat moss. Caladium does not like to be stored cool. The tubers will be damaged as a result. Choose an area that is dark, well ventilated and about 65-70 degrees.

Canna

Canna is very easy to store. After a frost has blackened the tops, dig the plants and cut back the tops to about two inches. Allow the clumps to dry and then store the entire clump, soil still attached, in bushel baskets or cardboard boxes in an area that is dark, well ventilated and about 45-50 degrees. In the spring shake off the excess soil, divide the clump so each division has at least three eyes and replant.

Dahlia

Dahlia should be dug after a very light frost. Dig the tubers and cut back the stems to about two inches and allow the tubers to air dry. After drying, place them in containers filled with peat moss or sawdust in an area that is dark, well ventilated and about 45-50 degrees. Dahlia tubers don’t like to dry out completely. When in storage, check on them regularly for signs of dehydration or shriveling. If necessary, mist lightly to add some moisture to keep them plump. Do not keep the peat moss wet however.

Gladiolus

Dig these plants in the fall after they turn yellow or after a frost. Cut the stems back to about one inch and allow the corms to dry in a cool, shaded area. Before storing, remove the old, shriveled portion (last year’s corm) keeping the plump, new corm. Store in dry peat, sand, or hang in mesh bags in a dark, well ventilated area at about 45-50 degrees.

Elephant Ears

These spectacular tropical plants are easy to store over the winter by allowing a very light frost to kill back the tops slightly. Dig the plants and allow the tubers to air dry. Cut back the tops and store the tubers in containers filled with peat in a cool, dark area.

“So, the next time you look out at your garden and see all of those fantastic summer flowering bulbs and worry that ‘old man winter’ will claim them for his own, think again,” said Stack. “Beat old man winter by digging, storing and once again reusing summer flowering bulbs saved from the garden of 2011.”