With large, often colorful leaves, and unusual, re-blooming flowers in bright happy colors, they add a lush, exotic look to garden beds and containers, re-energize a hot and humid summer garden, and are even happy in boggy ponds or in container water features on a partly-shaded patio.The thick, fleshy rhizomes can be easily stored in a cool basement, garage or cellar in total darkness – no heat lamps, timers or expensive lighting systems required.Cannas spread vigorously, forming clumps of thick, fleshy rhizomes held close to the soil surface.In fact, even if you do have a greenhouse, it’s much easier to store them in a garage, basement, crawl space or unheated spare room.You might have a friend who doesn’t mind housing a plastic bag of maintenance-free rhizomes in their cellar – particularly when you share a few in the spring!Using an unheated cold frame in the early spring months can help you get the foliage going earlier in the season, but even if you don’t, you’ll find your cannas can’t wait to get started again once the temperatures warm.While cannas are sending tropical foliage skyward during the growing season, they are also spreading into the soil, creating shallowly-rooted clumps of thick but brittle rhizomes.If you are north of Zone 8, mid-autumn and frosty temperatures will signal that it’s time to dig those rhizomes for winter storage.Waiting also allows you to get the most from your cannas – they will continue to grow and produce flowers often late into the autumn, adding much to the fall garden.However if they were located in a boggy condition or in a water feature (cannas make great pond plants!If you’re digging several types at the same time, put them into large, labelled trugs (even if it’s just a scrap piece of paper thrown in with them).Traditional methods advocate placing them in containers or bags filled with slightly dampened peat moss or wood shavings, but for those short on time or either of those materials, cannas can also be overwintered simply by placing the sorted rhizomes into heavy duty garbage bags and storing in the correct conditions (see below).As temperatures increase and spring returns, re-inspect your rhizomes – throw away any that are rotten or diseased and if some are beginning to sprout in storage, lightly dampen with water to replenish resources.At this point you have two choices: Either wait for the right time in the garden to plant, or force them into earlier strong growth using a cold frame or greenhouse.Whichever route you take, plant the rhizomes 3-4 inches deep in rich soil approximately 1’ apart with a small amount of balanced fertilizer.Keep your storage areas cool, and when all danger of frost has past, re-plant outside or in containers in rich soil with a small amount of balanced fertilizer.When all danger of frost is past, replant the cannas in containers or garden beds at the same soil level they were in the pots.
Edward R. Forte
Author