How to Grow Cannas

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Cannas are a rhizomatous tender perennial with attractive green, bronze, bronzy orange, rich scarlet, purple or striped foliage that come as dwarf, medium and tall plants. Cannas come in a wide range flower colours from pale cream, lemon, apricot-pink, white, gold to vivid yellow, orange, red, scarlet and deep crimson. The flowers may be fringed, striped or self-coloured.

The tall forms make good subjects for the larger tropical garden or by the pool and are often grown for their leaf colour. "Tropicana" for example has deep crimson leaves striped in deep green to black that often appear luminescent when caught by the light. "Bengal Tiger" with it's green and yellow striped leaves is another cannas commonly used to give a jungle look to a garden.

Cannas x generalize is the name given to the many cannas x hybrid cultivars available that are often grown in tropical beds or along a driveway where they are grouped into one colour. In the general garden cannas can be skilfully blended into a border or used as a foliage backdrop plant. Look for cultivars with golden striped foliage to add colour contrast for borders or bedding schemes. Cannas do well in tubs or large containers where they look good with low growing foliage plants.

Although cannas are hardy they do best in areas with consistently warm summers. They grow well in semi-shade but produce the best blooms when grown in full sun.

Plants can be obtained from a nursery, grown from seed or from root division if you know someone with plants to spare. Plant in a rich humus soil about 45-60 cm (18-24 inches) apart in a bed that has be well dug over and heavily manured and fertilised.

To grow from seed I have found it best to soak the seeds in tepid water for 24 hours first before planting in potting mix in individual pots. Keep in a warm place until germinated then transplant out into the garden.

Plants can quickly become overcrowded with the soil may no longer able to support them. This can cause the flowers and stems to grow progressively smaller. To maintain vigorously growing plants with strong stems and large flowers remove stalks that have finished flowering by snapping off at the base with a sharp tug at ground level. Divide clumps in spring every second year. Discard old rhizome root stock and replant only those with strong young shoots.

After the first year's flowering cut back all the stems to ground level and give the soil a good topdressing of well decayed stable (or animal) manure in which there is plenty of straw (if you can obtain it) otherwise use well-prepared compost. As soon as the growth resumes again give a side dressing of balanced fertiliser.

Sometimes variegated Cannas such as "Bengal Tiger" will start to loose their gold stripes and revert back to plain green leaves. This can be caused by a number of factors including lack of light, too much nitrogenous fertilizer or a reversal of the original genetic mutation that created the stripes in the first place.

In subtropical or warm temperate areas cannas will flower for most of the year. They like moist soil so keep watered well during dry weather conditions and keep on eye out for slugs and snails who enjoy dining on the leaves and flowers.

Garden and Outdoor Living