Storing tender, summer-flowering bulbs, corms, rhizomes and tubers for winter

Give tropical or subtropical plants a future next summer by storing bulbs, corms, rhizomes and tubers now.

Bulbs of Colocasia or Elephant Ears need to be stored during winter. Photo by Netha Hussain, Wikimedia Commons.
Bulbs of Colocasia or Elephant Ears need to be stored during winter. Photo by Netha Hussain, Wikimedia Commons.

Many gardeners begin adding to their gardens as they learn about new plants and want a new look for their flower beds. Many have already added spring-flowering bulbs that can stay in the ground all year. But with interesting plants like Colocasia or Elephant Ear, or some of the Cannas with bright, striped foliage, these plants are going to be treated differently. If these tropical or subtropical bulbs, corms, tubers and rhizomes remain in the soil over winter, they will freeze and die. Some other tender, summer flowers include Gladiolus, Caladium, Tuberous Begonias and Shamrocks.

The time to store these bulbs, corms, rhizomes and tubers is now or in the very near future. You are waiting for the first killing frost of fall. This is that cold night that kills the tops of many plants, especially those summer-flowering bulbs. The plants can stay in the ground longer if you choose, but must be lifted before the ground freezes. If the stem begins to rot, it is always possible for that rot to follow the stem to the bulb. You also do not want to be digging up these plants when the air is cold enough to damage their little, naked bottoms.

When ready, prune the top of the dead, limp stem off 3-6 inches above the bulb. The bigger the plant, the longer the stem is cut. This is going to act as your “handle” for moving the plant, but most importantly, it is going to prevent damage to the bottom of the plant. If the stem was cut flush above the bulb, it may cause rots to develop in this area. By allowing your handle to shrivel and dry up and then shortening it, there will be no decay in plant paradise.

Dig far enough from the plant that you are not going to hit any important parts underground. Carefully brush the soil off of with your fingers or a soft brush. Do not wash the bulbs because you are trying to dry them out and getting them wet will slow the process. The skin on the bulbs is damp after being dug and very tender, and you do not want to scrape it. Gently place the bulbs into a bag, basket or box and bring indoors to a heated area as soon as possible. The bulbs need to be placed on several layers of newspaper or cardboard separately with none overlapping or touching. They should be out of the sun but with dry, warm, circulating air. Every few days, turn the bulbs over so all sides dry evenly. This drying period is toughening the skin so the bulbs will store well. This is also done with potatoes from the garden. You can label bulbs with a marker if you need to identify them later.

Inspect the bulbs for damage or anything to indicate they may rot during storage. After two weeks, recut the plant stems. If the stems are dry on the inside, the bulbs are ready to store. Bulbs do best if stored in a container filled with something to cushion the bulbs and prevent them from touching. This also helps to prevent excessive drying. Bulbs that are shriveled in the spring may not grow. Dry Sphagnum peat moss is ideal because its acidity can stop small rots in their tracks. You could also use wood shavings like what’s used in pet cages. Do not use wood chips because they may damage the stored bulbs. Other materials can be used. Tiny bulbs like Shamrocks that are smaller than unpopped popcorn can be grouped and placed in mesh citrus bags like one that originally held key limes.

Use a cardboard box, paper bag or basket and start with a layer of packing material on the bottom. Then, begin layering the bulbs and adding fill. Bulbs should not touch. Store the filled container at approximately 45 to 50 degrees Fahrenheit in a darkened area. If the location is too warm, bulbs may begin to grow and if it is too cold, they may be damaged. Michigan State University Extension recommends putting a thermometer near the stored container and checking it periodically.

In the spring, any bulbs that need to be divided should be before planting. Plant them after all danger of frost has passed or pot them up and grow them indoors like a houseplant so they will be a larger size when they do move to the garden. These tender flowers can add a little or a lot of exotic color or leaf size to your Michigan garden. By storing them over winter, you put them on hold for another blooming opportunity.

Did you find this article useful?