This is the time of the year that cannas bring that exotic touch to the garden.
This year cannas have grown very well, the early moisture in spring and the heat over the summer months has produced large leaves with lots of flowers. Cannas are tender plants, easy to grow, which have exotic banana like foliage and large colourful flowers. In Victorian times there was a great interest in cannas and many hundreds of varieties existed. Due to lack of interest in the intervening years many varieties have been lost.
There is a renewed interest in cannas and many varieties are now available with flowers in shades of red, orange, pink and yellow. Flowers are often bicolour with blotches, spots and streaks of different colour.
The foliage is also very attractive and comes in shades of purple, bronze, red, green and striped. Cannas can range in height from a few feet to as much as ten feet tall. Cannas are very strong and sturdy plants which require no staking. We treat our cannas a bit like our dahlias, some of the hardier ones are left in the ground over the winter.
The rest are dug up, leaving the lifted plant as an undisturbed solid clump and stored in a frost free place. In spring the solid clump is divided and potted up. Canna rhizomes do not normally enter a totally dormant stage and if they dry out, some rhizomes may be lost. This is perhaps one of the reasons why some garden centres do not stock canna rhizomes.
Cannas are easy to grow. You can buy cannas as rhizomes from your garden centre and pot them up in any multi-purpose compost in late March or early April and place them in a greenhouse or warm place.
The earlier the rhizome is started into growth the sooner it will flower. Plant out into the garden at the beginning of June and they should start to flower from August and continue on flowering until the first frost. When planting out prepare the site well. The site needs to be dug, the deeper the better and lots of well rotted manure or compost added.
It is impossible to overfeed cannas. The ideal location for a canna is a warm, damp, sheltered place. Instead of buying canna rhizomes you may buy canna plants already potted up from your local garden centre.
Cannas may also be grown in pots or tubs and placed in your patio or conservatory to delight and amaze visitors to your garden. There are dwarf varieties which flower earlier than the larger ones. If planting in pots or tubs, again the message is, lots of rotten manure.
The variegated cannas are the most popular. Canna ‘Durban’, sometimes sold under the name ‘Tropicana’, appeared a few years ago causing a sensation. It has stunning colourations with pink veins on a dark purple leaf with an orange flower. Canna ‘Striata’ has yellow veins on a green leaf with an orange flower. Canna ‘Black Knight’ has bronze foliage with dark red flowers. Canna ‘Stuttgart’ is a recent plant, introduced from USA in 1998, has green foliage with large white veins and apricot flowers.
Once smitten by these wonderful plants you will want to grow more and more varieties of these wonderful plants.
Jobs for the week
Gladioli plants which have finished flowering should be lifted from the ground before they are damaged by frost and excessive frost. Dry them off in the greenhouse before cleaning off the soil and cutting back the old foliage and flower spikes.
Now is a good time to plan out a herbaceous border if you want a spectacular display next year. Dig the ground and remove all perennial weeds, add in plenty of compost or well rotted manure. Choose plants that will provide a long season of interest and a succession of flowers.
Plant a number of each variety to create a bold drift rather than having plants dotted around the place. Most plants in the herbaceous bed will have finished flowering at this stage, do not cut old dead stems until next spring, they provide shelter for the new emerging shoots and a place for beneficial insects to hibernate over winter.