Cannas - classification of flowers and dealing with diseases and insects
Cannas flowers - dealing with diseases, insects and pests
Disease and Insect, pest: Canna is a hardy plant not much affected by disease and pests. Although some bacterial and fungal diseases like bud rot (Xanthomonas sp.), rust (Puccinia thaliae), stem rot (Pellicularia rolfsii) and canna mosaic virus may infect the plant. Diseases can be prevented by using only healthy rootstocks, regular spray of fungicides like Bavistin @ 2 gm per litre, avoiding over watering, overcrowding and rouging of infected plants.
During rainy season some insects like Japanese beetle (Popillia japonica), mites and yellow woolly bear caterpillar (Diacrisia virginica) may damage the foliage and flowers of the plants. Repeated application of sprays containing Rogor or Sevin @ 1 ml per litre are needed to control this pest from doing serious damage. Mite populations can be controlled by regular spray of Kelthane or Propargite at the rate of 0.03 % per litre. Classification of Canna flower plants
Modern cultivars of Canna are divided in two classes:
- Orchid flowering. In this group, flowers open one by one and not together, e.g. Salmon Yellow, King Humbert, etc.
- Truss flowering. In this group, flower open together and they are mostly used for impressive display of colours.
Canna varieties are also classified according to their height.
Tall varieties of Canna flowers - These grow 80-160cm tall. Some of the major varieties are:
- Red - Statue of Liberty, Sunset
- Pink- Apricot King, Dorris
- White- White King, Radio
Dwarf Varieties of Canna flowers- These grow 50-80cm tall. Some of the major varieties are:
- Orange- Orange Glory, Cleopatra
- Pink- Hungaria, Departing Day
- Yellow- Star Dust, Apricot
The varieties have also been categorized as having flowers that are spotted, bicoloured or margined with other colours and these are preferred over self coloured flowers, e.g.
- Bicoloured - Olive, Dream, Sweet Heart
- Spotted - Queen Elizabeth, Goliath, Gladiator
- Margined - Rosemond Coles, Masterpiece, Star of India
In some cultivars foliage is ornamental and bronze-purple in colour which is different from the usual green foliage. Some varieties having bronze-purple leaves are Lord Buddha, Aga Khan, Rose Queen, Sun Set, Black Knight.
Trinacria variegata is a variety with variegated leaves.