Wednesday, June 2, 2010

Big Colorful Cannas by Gardener Dave

The Canna Lily is one flower that is frequently overlooked by Front Range gardeners. Perhaps the tropical nature of this showy plant gives pause to raising it in our climate of rapid temperature changes, or perhaps the stated need to dig them up in the fall and store them over winter intimidates many.
Cannas grow from large, starchy rhizomes. Interestingly, they are not true lilies, but are more closely related to gingers and bananas, hence the broad attractive leaves the plant produces. When the rhizomes dry, they may look dead, but will quickly revive and swell when water is applied to their soil.

I have minimized the care needed for growing my cannas by using the following method.  I plant them in a bed on the SE (front) side of my house
in enriched soil, water them well during the summer months, and let them go dry under about 5-6 inches of shredded bark mulch during the winter.  The minimal heat from the house foundation seems to keep them from freezing in the coldest winter so they are ready to come back up each spring. The brick wall of the house helps to stabilize temperatures during the summer, giving them more even warmth day and night. Being tropical, they do like warmth and moisture. They form a background for the shorter plants in the rest of my front flower bed, growing about 4-5 feet tall and produce showy blooms from late June to frost. My cannas are mostly rich basic reds, oranges and yellows, but many other colors – even variegated ones – are available. They do well with about 6-7 hours of sun, but will gladly take full sun. You have probably seen them used as tall, showy central plants in many public park gardens. I do dig mine up about every 3-4 years in the spring, then add more fertilizer and compost to the soil, divide them and usually have more roots than I need, so I share with friends.

Cannas also serve will as an upright “Thriller” in a large pot with other lower plants.  Make sure the pot is large enough and heavy enough so it will not tip in a strong wind.  Better yet, put the pot in a sunny place out of the wind to protect the large blooms. When the blooms fade, cut the stalk just below the spent bloom and the plant will produce more blooms. Keep the pot evenly watered and fertilize with a general-purpose fertilizer monthly to keep the blooms coming.

Gardener Dave