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Canna (cultivars)

English
  • Annuals, perennials and bulbs
Canna x generalis 'Wyoming'
Photo: Jardin botanique de Montréal (Michel Tremblay)
Canna x generalis

Onglets

Botany

Origin and description

Cannas are native to tropical and South America
Spacing: 30 cm
Height: 120 cm
Depth: 10 cm

Species, cultivars and related plants

The Canna genus includes some twenty-five species of rhizomatous perennials.  

Some of the species and their many cultivars are generally cultivated as ornamentals: Canna hortensis, Canna indica and Canna edulis – the latter has an edible rhizome. It is boiled and eaten in South America and starch is extracted from it in Queensland, Australia (Queensland arrowroot).

Common name

Canna

Latin name (genus)

Canna x generalis

English common name

Canna

French common name

Canna

Botanical family

  • Cannaceae
Horticulture

Growing conditions

For optimal blooms, cannas need full sun and humus-rich, moisture-retentive soil. In the shade, they tend to produce more leaves than flowers.

Plant the rhizomes directly in the ground once all danger of frost has passed or in pots indoors in early April to give them a head start.

Cannas are not hardy in Quebec. Cut the plants back to the ground before the first frost in fall and dig up the rhizomes. Let them dry for a few hours before storing them in a cool, dry spot (10-15°C) for the winter.

Plant out: mid-May
Dig up: October, after the second frost

Pruning and maintenance

Spring
The rhizomes can be separated using a knife so that each section has between one and three eyes. Then, we suggest that they be sprinkled with sulphur to prevent disease.

Canna should be separated and potted up in early April. It is also possible to wait until May so they can be planted directly into the garden.

Fall
Care and storing of cannas is much the same as for begonias. It is advisable, however, to remove the rhizomes from the ground on a sunny day and leave them upside down for three or four hours so that water can drain from the stems. There is no advantage to leaving the clumps outside later than October 15.

Propagation

Rhizome division
Seed: Harvest the seeds in fall, once the pods are thoroughly dried. The hard, black seeds look like large peppercorns. They can be stored for more than twenty years if kept dry and cool. Sow them indoors in early spring in warm, moist potting soil, after first soaking the seeds in warm water for 48 hours. You can also place the seeds in a plastic bag filled with damp peat moss, leave them at 23°C for several days until they germinate and then pot up the seedlings. Scarifying the seeds seems to increase the likelihood of germination. Make a small scratch near the hilum (the “eye” of the seed). Do not scratch the hilum itself, or you will damage the embryo.

See also

Pests and diseases
  • Aphididae

    Aphids

    There are thousands of species of aphids in the world. These tiny, highly prolific insects feed by sucking the sap from a wide range of ornamental and food plants. They form dense colonies on young shoots and under leaves, and also feed on plant stems, bark, roots and fruit.

Physiological disorders