How can anything so breathtakingly beautiful be called old fashioned? Almost without exception modern garden books refer to the canna as old fashioned. It is true that the canna has been known for generations, but certainly it is no older in fashion than the rose or the lily.
What is outdated about the canna is the method of planting, just as roses and lilies have been hybridized, so has the canna, and now gorgeous blossoms top plants that once were prized only for their ornamental leaves, their blossoms being merely a secondary consideration. The definitely outmoded method of planting in round or oval shaped beds in the center of a small lawn is the thing that has brought the canna into such disrepute. Nothing is more discordant than a few small spikes erupting from the center of a lawn.
The Right Setting
Cannas are a stiff, rather formal plant, and they need the proper setting to display them to best advantage. Plants should be selected of a variety and height to suit the location where they are to grow. They may be used as a background plant where their leaves will provide a background setting for the many colorful annuals.
One of the most effective arrangements l have seen was a fence of snowy white brick serving as a background for the brilliant green leaves and the velvety red blossoms of the canna plant. Added to this striking picture was a gate of white-painted wrought iron. The term old fashioned could never be applied to the beauty of this yard. Despite the wrought iron, white-painted brick, and the cannas, it was emphatically modern! Another colorful use of the canna may be achieved by planting the bronze-leafed variety with its tawny orange blossoms in front of the tall redwood fences which grace the back yards of many homes today.
The canna is a summer bedding plant. It will not tolerate frost, and therefore it is sometimes started indoors in pots or flats in areas where the spring weather is uncertain. In this manner the growing season may be lengthened. The soil in which rootstocks are planted should be warm enough for tropical plants; that is, it should be about 65 degrees at a depth of six inches. Plants started in the hothouse in soil and peat moss should be planted in April. Those grown in heated beds may be started in May. If they are to be planted in the open beds, it should be after all danger of frost is over. Otherwise the plants may be stunted in their growth or even killed.
To grow successfully, the canna needs the heat of midsummer, with plenty of sunshine. Cannas are a genus of tropical-flowering plants belonging to the banana family and must be treated with similar care.
Care and Feeding
Select a bed where the plants will receive a maximum amount of sun and prepare the soil 18 to 24 inches in depth. Dig out the rocks and add loam if the soil is very rocky. It should be good rich loam with the addition of a generous amount of well rotted organic material. Cannas require an abundance of plant food. The fertilizer should contain a high phosphoric content. Too much nitrogen or lack of sunshine may result in small plants or straggly blossoms.
Canna rootstocks grow in clumps which become rather matted. These are divided in the spring before replanting. They should be cut with a very sharp knife so that they contain at least one, but not more than two “eyes.” Rootstocks should be spaced about 18 inches apart. They are planted a little deeper than iris rhizomes, perhaps about two inches under the surface.
Canna culture is very similar to that of dahlias, with the exception of planting depth. After the bed is prepared, space the rootstocks along the bed as you want them to grow. Mix a handful of bone meal in the soil beneath the rootstock. Put the root in place with the eye turned up. Gently firm the soil over the rootstock and then moisten the entire bed with a sprinkler hose or a nozzle sprayer.
The same procedure is followed in setting out plants already started in pots, although it is best not to disturb the soil around the roots of the plant. Tap the pot lightly on its edge and lift the entire root system and dirt from the pot. It is a good idea to slope the bed a little toward the edge to allow good drainage. Too much water allowed to stand can cause the roots to rot, although generous watering throughout the summer is necessary for the large showy blossoms.
Winter care for cannas is very similar to that of dahlias. In the lower South plants may be allowed to remain in the ground the year around, although they should be dug and separated every four or five years. After the first frost, clear away the withered leaves and take care of any insect infestation which might cause injury to the rootstocks.
Digging and Storing
In colder areas where the roots might freeze, it is necessary to dig the plants after the first light frost and store them for the winter. After the leaves are killed by the first frost, cut the tops of the plants and allow the roots to ripen for about a week. Since most cannas have huge root systems, it will require quite a bit of pressure to raise the plants from the ground. However, be careful not to break the roots. Turn the root system upside down to dry thoroughly before storing.
When they are completely dry in a week or two, they may be taken apart easily. It is possible to divide them either in the fall or spring, but most gardeners like to make the divisions in the spring as they plant the rootstocks. Unless the rootstocks receive proper care, they will either shrivel up and bloom poorly or will completely rot away. To protect the roots during storage, store them loosely in paper bags or boxes between layers of peat moss, in a cool dry place.
One of the bountiful rewards of growing cannas is their apparent immunity to most diseases and insects. This is indeed a boon to a busy gardener. Occasionally leaf rolling caterpillars will attack the plant, especially in the South. These may be controlled by hand picking the insects or by spraying with a prepared spray of Sevin. Another enemy sometimes encountered is bud rot, a black decay of the young tissues. The best remedy for this is selecting healthy plants for rootstocks and avoiding overwatering. This disease can extend from the buds into the stem of the plant and may ruin the entire plant.
Todays hybridized cannas no longer resemble the older plants which were sometimes called “Indian shot” because of the seed pods they grew. The newer plants are much shorter and have a gorgeous range of color in their huge showy flower clusters. They have been developed in colors which range from pure white to fiery scarlet, including yellow, rose, scarlet, ivory, and crimson.
The new dwarf cannas are exceedingly popular with the small home owner. Their diminutive size requires less space for a proper setting. Some varieties are only 30 inches high when in full bloom. These same varieties may be used to provide indoor displays in the winter. This may be done after the curing process is completed in the fall. Place the rootstock in a large pot. Keep the soil moist until the new growth appears. Then place the pot in a sunny window, feed with soluble plant food, and water well. The blossoms will be a welcome addition to a dreary winter window scene.
