116 3rd St SE
Cedar Rapids, Iowa 52401
The Iowa Gardener: How to dig and store summer-blooming bulbs
I never used to bother with digging and storing summer-blooming bulbs, such as dahlias, gladiolus, elephant ears, and more. I thought it was too much work. But last fall I was in a friend’s garden and she urged me to dig up some of her dahlias to store and plant so I gave it a try.
I’m hooked! It was easy, they stored well, and I was able to save probably $50 to $75 worth of plant material in less than 30 minutes.
Most spring-blooming bulbs, such as tulips, daffodils, crocuses, hyacinths, and irises are winter hardy. So are most true lilies. But some tropical natives need to be dug up, stored in the dark indoors, and planted outside again in spring. These include dahlias, gladioli, elephant’s ear, cannas, caladiums, and tuberous begonias.
Tuberous begonias are very tender and ideally should be dug up before the first hard frost. The others should be dug up after a hard frost, once they’ve gone dormant. Here’s how.
- Use a spading fork or shovel to gently excavate the dahlia roots, taking care not to damage them. Insert the tool a few inches away from the base of the plant and gently lift it out of the ground. Gently remove as much soil as possible without causing harm to the tubers. Save only healthy plant parts.
- Trim back the foliage, leaving about 2 inches above the tubers/roots.
- Label. This will help you identify them when you plant them in the spring. You can do this in any way you want as long as it works for you. I like to use a piece of cardboard, pierced with a nail and threaded with a length of string that I tie onto the tuber.
- Spread the tubers out, indoors or out, in a cool (not freezing), dry place with good circulation on newspapers or spread out in a cardboard box or two. This helps the tubers heal any cuts or wounds and toughens up their skins a bit, reducing the chance of rot.
- Once cured, place the tubers in a storage container that breathes, like a cardboard box or a crate, filled with peat moss, perlite, or sawdust. Some gardeners swear by shredded newspapers. These materials help maintain proper moisture levels and prevent the tubers from drying out or becoming too damp. Store them in a cool, dark, and well-ventilated space, ideally around 40 to 50 degrees. It’s important that it never gets down to freezing. I store mine in my basement.
- Check on them once a month or so during the winter to ensure they're neither shriveling up nor rotting.
In spring, after all danger of frost has passed (mid-May in the Cedar Rapids area), plant outdoors once again to enjoy the color and beauty — at no additional cost — of your labors.
Veronica Lorson Fowler is co-publisher of the Iowa Gardener website at www.theiowagardener.com.
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