Canna Canna

Cannas, or Arrowroot, is a tall, leafy, tropical plant with gladiolus-like flower spikes that bloom atop erect stems sheathed in large paddle-shaped leaves. Despite the common name, Canna Lily, it is not a lily. The Canna genus includes about 10 species with numerous cultivars. Commercial growers typically sell Canna plant cultivars that range from 1.5 feet tall to 8 feet tall with flower colors that include red, orange, pink, yellow, cream and some bi-colors. The foliage colors can also vary from shades of green or bronze to striped/variegated and provide ornamental value when plants are not in flower.

Cannas can be a challenge to grow. Although it is a tropical plant, most cultivars have been developed in temperate climates and are easy to grow in most countries of the world as long as they receive at least 6–8 hours average sunlight during the summer, and are moved to a warm location for the winter. They do best in moist, organically rich, well-drained soils in full sun. However, rhizomes may rot in poorly drained wet soils. In USDA zones 7 through 10, you can leave rhizomes in the ground; however in zones 5b and 6a, you should dig up the rhizomes in fall and store the bulbs over winter. The plants will sustain injury if left in the ground at temperatures below 25 degrees F. Cut the plants to the ground immediately after the first frost and lift the rhizome clumps for winter storage in a dry medium such as peat or vermiculite and store in a cool dry location than does not fall below 40 degrees F. In the spring, you can return the rhizomes to the ground, placing them 4 to 6 inches deep after threat of frost has passed. After the blooms have faded in late summer, remove the flowering stems. If you grow the plant in containers, stored them in their containers over winter. As finicky as the plant sounds, it does tolerate drought and poor soil, but prefers a rich, well-drained soil with abundant water and a site that gets full sun in the morning. 

Insects, Diseases, and Other Plant Problems:  Common diseases include aster yellows, bud rot, rust, and mosaic virus. Rabbits, Japanese beetles, caterpillars, slugs and snails have been known to chew on the foliage.

Quick ID Hints:

• Tall erect herb with giant, sheathing leaves
• Terminal racemes with large carotenoid flowers
• Fruits a prickly 3-valved capsule.

Gigantic erect, succulent herb.

utilized in massing, background plants in beds, center plant in smaller beds, container plants, highway color in beds by DOT; rhizomes need to be dug up and stored overwinter in colder climates; numerous cultivars, including dwarfs. 

GLADIOLUS GROUP - staminodes broad, overlapping, flower appearing more full; more popular selections. 

ORCHID GROUP - staminodes narrow, segregated, flower appearing smaller & more exotic. 

Prefers full sun in rich fertile soils; intolerant of killing frosts; numerous pest & disease problems.

VIDEO Created by Elisabeth Meyer for "Edibles, Bulbs, and Houseplants" a plant identification course offered in partnership with Longwood Gardens.