If you crave bold accents and lush tropical foliage in your garden, then cannas are the plants for you. These bold beauties have made a big comeback, and canna rhizomes of choice varieties regularly sell out in stores and catalogs. Cannas are easy-to-grow, relatively inexpensive, dramatic additions to tired old flowerbeds. With a huge selection of flower and leaf colors, there is sure to be a canna that will add pizzazz to your garden.
Cannas will grow almost anywhere, as a perennial in the South and a summer flowering plant whose rhizomes can be easily lifted and stored in the North. There are cannas for large spaces and tiny cannas just right for containers. While the flowers of some varieties of cannas are the show, in others it's the huge, tropical-looking foliage, and in many modern varieties, it-s both. Cannas are indeed tropical plants, flourishing in heat and humidity.
Canna leaves are usually large and broad, with a heavy rib down the center. They can be various shades of green, burgundy and red, often with splashes of white or yellow or stripes of color following the leaf veins. Depending on variety, cannas grow from 16 inches to 10 feet in height. The rhizomes increase horizontally underground, throwing up new shoots until the plant becomes a huge clump.
The flowers of cannas come near the end of summer, on long stalks at the top of the plant. They are often described as orchid- or gladiolus-like. They can be large and striking in modern varieties but may be smaller and less glamorous in some older cannas. Canna flowers come in all colors and color combinations, except blue, purple or true white. Canna seed is a hard, round, black ball, which gives cannas the common name of Indian Shot.
Cannas are usually purchased as bare rhizomes in the North and as rhizomes or potted plants in the South. Look for rhizomes that are large and firm with two or more buds on them.
In the North, start rhizomes indoors about six weeks before your last frost in pots of good, rich potting soil. The pots should be in a warm, sunny area and kept well-watered. The rhizomes may also be planted directly in the ground after the last frost when the ground is warm, but they may be slow to start growth and late to bloom. In frost-free areas, the rhizomes can be planted at any time. While a frost may kill all the foliage in some areas above zone 8, the rhizomes will survive underground if protected with mulch. I have had cannas survive Zone 5 winters in a protected area, although they are so slow to start growing in the spring that they seldom have time to bloom before fall. In Zones 6 andand above, consider lifting the rhizomes and storing them during winter. In Zone 7 a heavy mulch after frost has killed the tops may be all the protection that's needed. In Zone 8 and below, cannas are generally treated as perennials that need little winter care.
Cannas give a lot to the garden but they are greedy guests needing lots of sun, lots of moisture, lots of heat, lots of fertilizer and lots of organic matter. Rich, moist soil in full sunlight is ideal for cannas. Cannas will even do well in pots sitting in water if there is some soil above the water. Fertilize cannas once a month with a fertilizer formulated for flowers and water frequently for spectacular results.
In the North, when a frost has killed the canna foliage, carefully dig up the rhizomes. You will probably find a few more than you planted. Shake off the dirt and allow the rhizomes to dry in the sun a few days. Don't allow them to get frosted or frozen while drying. Then store the rhizomes in a cool but frost-free place in sand, peat or vermiculite. Before planting, you can divide large rhizomes as long as each piece has at least one bud, preferably two, to a section. You can trade or give away the excess if you have more than you care to plant.
There are so many wonderful cannas on the market now that you will be tempted to become a collector. Small canna varieties include Dwarf Wyoming, with gold flowers and dark-maroon veined foliage; Pink Surprise, with hot-pink flowers edged with yellow and green foliage; Bankok, with bright-yellow flowers and green foliage striped with white, and Lucifer, one of the smallest, with scarlet-red flowers touched with gold and green foliage. Large canna plants include Australia, almost black foliage and hot-red flowers; Tropical Sunrise. a blend of peach, pink and yellow flowers with green foliage, and Cleopatra, an always-changing mosaic of red and yellow flowers and green leaves marked with purple in various patterns. Constitution has narrower leaves than other cannas in an odd gray-purple shade and pastel pink flowers. Ermine has very pale, almost white flowers and green leaves. Tropicana leaves are boldly striped in yellow and red on a purple background with screaming orange flowers. Stuttgart has lovely green foliage with white and peach-colored flowers, and the classic King Humbert offers golden-yellow flowers with red spots and green leaves. Some extreme cannas grown for their foliage are Musafolia, up to 10 feet high with huge, broad leaves that are green edged with red, and Intrigue, a canna with unusually narrow, gray-green leaves that grows up to 7 feet tall.
Tall cannas are accent plants in garden borders, the center of island beds or a backing of other beds. The foliage is often more dramatic than the flowers. Tall cannas can also be used as a screen, or flowering hedge. Smaller cannas can be used anywhere in beds to give late-summer color or foliage color and texture, and they are excellent for containers. Cannas can also be used as accent plants in water or bog gardens.
Forcing bulbs indoors means encouraging plants to grow and flower out of their natural environment and season. It can give you colorful flora, even in the dead of winter.