Cannas are grown as much for their attractive foliage as for their flowers. They are not true lilies but are in the family (Cannaceae). Garden variety cannas are usually hybrid plants developed from two or more wild species. Most of these species come from the subtropical regions of South America. Cannas thrive in warm climates like Florida and California. With protection they can also be grown in temperate climates. Colder regions can grow cannas as an annual plant.
Cannas emerge from underground rhizomes. The large oval leaves unfurl as they mature in early summer. The tall stems appear after the leaves are up. The leaves are held well above the plant creating an interesting presence. The tall flower spikes present themselves in late summer. Canna lilies continue to bloom from mid-summer until fall. They will die back completely at the first freeze.
Canna foliage is around 3-4 feet tall. The flower spikes can add another two feet to the height of the plant. There are also dwarf cannas that are 2-3 feet tall. Cannas are available in a number of foliage and flower colors. They can have green, bronze-red or even striped leaves. The flowers are available in yellow, pink, white, orange, salmon and red. There are also water cannas developed for ponds and water features.
Designing with Cannas
Cannas add a tropical feeling to any garden.They look good planted with banana, phormium, yucca, palm, ginger and other plants with large foliage. Many cannas have hot colored foliage and flowers. Plant them with other brightly colored perennials. They are very attractive in large clumps near entry ways or patios. They can also be planted in large containers to make a bold statement.
Cannas love very moist soil but do fine with regular water. They love loose soil that is rich in nutrients. Mix compost into the hole when planting cannas. If they are to remain in the ground, top-dress them with compost each year. Canna lilies bloom best in full sun. They can be grown as foliage plants in partial shade. In most regions they endure few diseases or insect problems. insecticidal soap can be sprayed onto the foliage if they are bothered by sucking insects. This will also discourage chewing insects like slugs and snails.
Storing Canna Rhizomes
Canna lilies withstand cool but not freezing temperatures. They can survive in USDA Zone 8 with winter mulch. They can be left in the ground safely in USDA zone 9 or higher. In cold climates the rhizomes must be dug up and stored over the winter. Dig up the rhizomes and separate them. Lay them out until they are completely dry on the outside. Place them in a dry material like saw dust or newspaper. An unheated garage is the perfect environment to store rhizomes.