Cannas: Add a Hint of Tropical Lushness to the Garden

Cannas are flowers that add height, color, and a hint of the tropics to the garden. Some types of cannas grow to six or more feet and are topped off by large plumes of flowers in yellow, red, orange, white or pink.

Cannas grow from rhizomes or large tuberous roots.

Clumps of cannas grow from thick tuberous roots that can be purchased from garden centers or mail order nurseries in the spring; they are sometimes purchased as growing plants in containers of a gallon or larger.

Buy healthy canna roots that are plump, firm, and have several "eyes" or buds. The roots should be planted horizontally five inches deep and two feet apart in a spot with at least six hours of direct sun. Good soil that drains well is best. Because of their size, cannas are planted in the back of a mixed flower bed. A large bed containing a single variety of canna draws attention in the landscape; it makes a major color statement.

Cannas can be started from seeds indoors in mid to late winter, but the seeds are harder to find and the plant will take several months longer to bloom.

Cannas have large oval leaves, similar to banana trees. The thick clumps expand rapidly as new tuberous roots grow below ground and send up additional shoots. A small section of root can produce a clump a foot across by fall. Cannas need plenty of water to keep them growing, one to two inches a week. Feed with a balanced fertilizer at least once a month. The plants bloom best if old flowers are removed.

Cannas flower from June to the first frost.

Flower clusters appear at the top of the clumps in mid summer and continue until frost. Traditionally tall cannas were the most popular, but varieties that grow only 30 inches tall are available. Some varieties have colorful leaves. Hummingbirds are attracted to the large funnel shaped flowers.

Cannas are not true perennials except in regions where there are no hard frosts, but they will sprout again each spring as long as the ground does not freeze deeply enough to kill the roots. The first frost will kill all foliage down to the ground.

Not a true perennial, cannas may need winter protection.

There are several strategies for dealing with the winter cold. If you live in an area where the ground is sure to freeze four inches deep, it is best to dig up the roots and store them inside through the winter. Some gardeners grow their cannas in semi-protected areas such as the south side of the house where the soil freezes less deeply. Other gardeners protect the canna roots by piling on a thick layer of mulch to insulate them from them cold. A deep pile of leaves held in place by twigs works well. But it should be removed in the spring as the ground warms up and the roots start to send up new sprouts.

As the clumps grow in size, they should be divided every couple of years to avoid overcrowding. Make friends with your neighbors by sharing your extra roots or start new beds of your own.

Cannas have few diseases or pests. Slugs eat holes in the leaves, but cannas grow fast enough so that it is usually not a serious problem. The scientific name is Cannas (hybrids). Cannas are native to tropical and subtropical parts of North and South America.