The canna lily, although not a true lily, is a popular flowering bulb that is easy to grow in many climate zones. The genus Canna includes 19 species of plants and many more have been hybridized. Cannas come in a wide range of flower and leaf shapes and colors. They bloom from the middle of summer until fall in sunny conditions. When you grow cannas in large decorative pots, they add a tropical touch to pool and patio landscaping.
History and Uses
Cannas are a tropical plant that is related to ginger, banana, heliconia and birds of paradise. They are native to the East Indies and South America. Europe saw its first cannas in the mid 1800s, and they remain popular to this day. The underground rhizome is a source of starch---some indigenous peoples and livestock have eaten this root. The young plant sends up edible shoots that are also eaten and residents of the Latin American countries add the seeds to their tortillas. The seeds also are made into jewelry, and in some countries they are included in musical instruments.
The "Pink Futurity" variety has pink flowers with dark red leaves. "Picasso" sports yellow blossoms with crimson spots. Cannas with pastel colored flowers include "Peach Blush," "Angel Pink," "Pink President" and "Apricot Ice." Many people prize the "Tropicana" for its stunning foliage, which is dark red with green stripes, and its brilliant orange flowers.
Plant canna rhizomes in spring in an area that receives full sun and which has well-drained, slightly sandy soil. Plant your rhizomes about three inches deep, with the pointed end facing upward. Lay down a four-inch layer of mulch and keep your canna well watered. Cannas do well if you fertilize them every month with a fertilizer having an N-P-K ratio of 5-10-5. Be careful not to over fertilize your canna.
Starting More Cannas From Seeds
If you want to make new plants from your canna you can collect and propagate the seeds. Allow some flowers to remain on the plant and then after the flowers die back for the summer collect the seedpods. Dry them for one week and then rub them with sandpaper to scarify the hard coating so they'll germinate faster. Soak scarified seeds in hot water for two days and then plant each seed ½ inch deep in a small nursery pot using a good potting soil. Keep your seedlings warm and moist all winter and then plant them in your garden after your final spring frost.
Dividing Canna Tubers
After your canna finishes its summer blooming period, dig up the plant. Separate the tuberous clumps by pulling them apart. Each chunk must have an "eye," similar to a potato, and must be firm with small shoots already beginning to form. Using regular potting soil, plant each clump in a small nursery pot and then cover the pots with a sheet of glass to speed rooting. Remove the glass every day to water your rhizomes and then take it off after they have started to form shoots above the soil. Move these plants into the garden after your last spring frost.