Cannas are showy perennials whose popularity has ebbed and flowed with the fashions of the time, with a huge peak in the 1800's during the English Victorian gardening era. Cannas are a plant that will always be popular with gardeners who like large, showy perennials…think petunias on steroids. Cannas are prized for their large, showy flowers which top the plant during the summer months. In reality, there are few perennials that can compare to the summer show put on by a nice planting of cannas. In 1986, we shared a large number of Canna 'The President' with our North Carolina Department of Transportation, who planted them along the Interstate highways from one end of the state to the other.
Canna plants are grown from a thick rhizome that grows horizontally just below the soil surface. In garden vernacular, these are mistakenly referred to as canna bulbs. In the garden, canna plants prefer organically and nutrient rich moist soils, where they will put on their best show. Although canna will survive poor soil and drought, their appearance will be far from appealing. Most canna also thrive when grown as an aquatic, but don’t overwinter in these conditions when temperature drop much below 20 degrees F.
There are a number of canna lilies to choose from in a wide range of heights and flower colors. Canna flower colors range from white to pink to red to yellow. There currently are no blue or purple-flowered cannas. Canna heights range from 2' tall to 8' tall and everything in between. Canna leaves range from solid green to nearly black purple, with some bearing glaucous blue overtones. Another factor to consider in selecting cannas are their spreading habit. Some canna species and hybrids are vigorous spreaders and will take over a large area, while others grow in a tight clump.
There are only two significant pests of cannas...canna virus and canna leaf rollers. Canna virus is a problem in plants that have been propagated with unsanitary tools which, unfortunately, includes most cannas. Starting in the 2000s, however, many canna lilies have been cleaned during the tissue culture process, so virus-free plants are now available. Canna leaf rollers cause the new leaves to roll together because of a caterpillar that spins a web for protection, snaring the new flowers. Canna leaf rollers are more of a problem where masses of cannas are planted and there is a critical mass of offspring for the following year. By cutting off the canna leaf tips while the caterpillars are still immature and spraying with a natural BT (Bacillus thuringiensis) product, you should get good control of canna leaf rollers. When you’re ready to select cannas for your sun garden, we know you’ll find some you like in our online plant catalog.