The canna bulb, also known as the canna lily, originated in the West Indies and South America, but this perennial is now grown all over the world and prized for its large, showy flowers, its unusual height, and its striking foliage. In some parts of the world, the undemanding canna bulb is grown for its food value, as well, and prized as an easily digested source of starch.
One of the traits gardeners prize in the canna lily bulb is its unusual height. It is available in 3, 4, or 6-foot varieties. The towering spikes of flowers and exotic-looking leaves can make a striking statement as an accent plant, planted in a large group, or as a background for other plants.
Keep in mind that the canna lilies may not reach their full potential in height if the growing conditions are less than optimal.
The canna bulb plant is closely related to ginger and banana plants. The root is commonly called a bulb, but it is actually a rhizome. Cannas bloom from early summer until the first frost, presenting spikes of four inch red, salmon, pink, orange, yellow, cream, or white flowers. Some of these flowers are solid, but others are spotted. The leaves are long, broad and flat. Foliage can be found in various shades of green, bronze, and reddish-purple, as well as many variegated types.
There are two basic types of canna bulbs that are commonly cultivated. The first type is grown for food. These canna achira have been selectively bred from canna discolor, for their edible rootstock, leaves and young seeds. Agricultural canna bulbs were once staple foods in Ecuador and Peru, and are still grown in parts of Asia and South America for the starch they provide.
The second type of canna bulbs are grown for decorative use in the garden or in pots. There are twenty different species of cannas, all of which originated in the Americas. Horticulturists have developed many interesting varieties that are available in a broad range of colors and sizes. These beautiful flowers are popular with gardeners the world over.
Choose canna bulbs that have at least two growing eyes. Prepare rich, moist, fertile soil in a spot with full sun. Plant the bulbs flat in their hole, an inch below the soil, 1 to 2 feet apart, after the danger of hard frost has passed. Water weekly and fertilize frequently with manure and a nitrogen fertilizer.
In recent years, canna lilies have been increasingly affected by several strains of virus, as have many other crops around the world. Research is currently underway to identify and eradicate these viruses, but at present, there is no way to guarantee that any bulbs sold or purchased will be free of disease. Symptoms may come and go, or the virus may lie dormant, exhibiting no symptoms at all for a period of time. Plants that are grown in the Northern United States and those grown in pots seem most likely to exhibit the symptoms of these baffling diseases.