How Long Does It Take for a Canna to Grow Once Planted?

North vs. South

• Depending on variety, cannas can have mature heights ranging from 2 1/2 to 7 feet with large showy leaves and flowers in shades of red, yellow-orange, pink and white. Below USDA zone 7b, cannas are reliable perennials. Above zone 7b, rhizomes need to be lifted and stored like dahlias, gladiolus and other tender summer perennials. Replanted in pots or in the ground, rhizomes can grow from bulb to flowering in 50 to 75 days. Bloom continues until fall.

Seed vs. Rhizome

• Seeds should be started indoors in February in zones 7b to 10 and moved outdoors as soon as they show sprouting leaves. Similar starts in colder climates may require supporting warmth and light to germinate and should not be placed outdoors until all danger of frost has passed. Northern climates may not provide enough sun and heat for first-summer blooms. Your local schedule for planting warm-weather summer vegetables like tomatoes furnishes a good guide for outdoor planting of cannas, whether rhizomes or seedlings.

Sun vs. Shade

• Cannas can tolerate partial shade but progress more rapidly in full sun. A planting in mid to late May can result in blooms as early as July. Ten varieties of native cannas grow in damp shady riparian areas in South Carolina, the Caribbean and South America. In general, however, hybrid cannas are highly heat- and light-tolerant.

Growing Results

• A North Carolina nursery describes cannas as "55 mph" plants. Preparations for the 1986 Olympics involved lining highways to Raleigh with cannas. Despite the challenges of traffic pollution and drought, the cannas provided an eye-catching welcome to visiting motorists. Both their rapid rate of growth and overall toughness made them a handsome highway-border plant.