Cannas are bold, tropical-looking plants grown for their attractive flowers and foliage. Flower colors include yellow, orange, pink, and red. The large, banana-like foliage may be green, bronze, or burgundy. The foliage of some varieties is striped or marbled in various colors. Most canna varieties grow to a height of 3 to 5 feet. However, there are dwarf varieties that grow only 1 1/2 to 2 feet tall. A few "giants" may reach a height of 8 to 10 feet. Cannas can be used as temporary screens, accents in beds, or as background plantings in borders. The smaller varieties perform well in large containers.
Cannas are normally grown from rhizomes. Canna rhizomes can be planted directly outdoors after the danger of frost is past (mid-May in central Iowa) or started indoors in large pots in March. The rhizomes should be planted 4 to 5 inches deep.
Cannas perform best in moist soils in full sun. They can also be grown in wet, poorly drained sites and shallow ponds. During dry weather, water plants once a week. To promote growth, fertilize in spring and mid-summer with a balanced garden fertilizer, such as a 10-10-10. Remove spent flowers to maintain their attractive appearance and promote additional blooms. While cannas have a few insect and disease pests, none are serious.
Gardeners can choose from numerous canna varieties. Some of the more popular varieties are listed below.
- 'Australia' - orange-red flowers, burgundy black foliage, 4 to 5 feet tall.
- 'Black Knight' - crimson red flowers, burgundy leaves, 3 to 3 1/2 feet tall.
- 'City of Portland' - coral pink blossoms, green foliage, 3 1/2 to 4 feet tall.
- 'Cleopatra' - yellow flowers with red spots, dark green foliage with bronze-red markings, 3 to 4 feet tall.
- 'Crimson Beauty' - rose-red flowers, green foliage, 3 to 4 feet tall.
- 'Intrigue' - light salmon flowers, green and burgundy lance-leafed foliage, 8 feet tall.
- 'Lucifer' - red flowers with yellow borders, green leaves, 2 feet tall.
- 'Miss Oklahoma' - watermelon pink blossoms, green foliage, 3 feet tall.
- 'Pretoria' ('Bengal Tiger') - orange flowers, yellow and green striped foliage, 4 to 6 feet tall.
- 'Princess Di' - creamy soft pink blossoms, green leaves, 3 to 4 feet tall.
- 'Red Futurity' - dark red flowers, burgundy foliage, 3 to 3 1/2 feet tall.
- 'Red King Humbert' - orange-red flowers, reddish bronze foliage, 5 to 6 feet tall.
- 'Richard Wallace' - golden-yellow flowers, green leaves, 4 feet tall.
- 'Rosamond Cole' - orange-red flowers with yellow edges, dark green foliage, 3 feet tall.
- 'Striped Beauty' - yellow flowers with white markings, green foliage with creamy yellow stripes, 3 feet tall.
- 'Stuttgart' - orange flowers, green and white variegated foliage, 3 to 4 feet tall.
- 'The President' - scarlet blossoms, green leaves, 3 to 3 1/2 feet tall.
- 'Wyoming' - orange flowers, bronze-red foliage, 3 to 3 1/2 feet tall.
In Iowa, cannas will not survive the winter outdoors. Canna rhizomes must be dug in the fall and stored indoors over winter. Cut the plants back to within 4 to 6 inches of the ground a few days after a hard, killing frost. Then, carefully dig up the canna clumps with a spade or fork. Leave a small amount of soil around the cannas. Allow them to dry for several hours. Afterwards, place the cannas in large boxes, wire crates, or in mesh bags. Store the cannas in a cool (40 to 50 F), dry location. Large clumps can be divided next spring before planting. Each section should have at least 3 to 5 buds.
This article originally appeared in the 4/6/2005 issue.