By Ralph E. Mitchell
UF/IFAS
Would you be intrigued with a flowering perennial plant named ‘King Midas’ or ‘Porcelain Rose’? How about ‘Red King Hubert’ or ‘Madame Butterfly’? These are cultivars of cannas that are well adapted to our hot Florida climate and are now in local garden centers. They not only have large flowers, some actually have colorful foliage and grow from under two feet tall to over six feet in height. Cannas can make a great versatile and sustainable impact in your yard.
Cannas are tropical to sub-tropical perennials that have foliage similar to a small banana. Their perennial nature provides colorful foliage ranging from green to greenish blue, and from purplish to yellow or white striped. Add flowers that come in ivory, yellow, rose, orange, salmon, crimson and red and you have a plant that will improve the looks of any landscape. Cannas are often used in borders or mass planted in round or square beds for a formal look. Cannas will benefit from the rich soil so consider adding several inches of well-rotted manure as you prepare the site before planting. Select a site that is full sun for best growth; some partial shade can be tolerated, however. Cannas generally come as potted plants or bare-root rhizomes that are planted one to two feet apart depending on the ultimate size of the specific cultivar. Supplemental feeding plus adequate water will help guarantee optimum blooming. Careful removal of the spent flowers will help promote subsequent flowering throughout the season.
Consider growing cannas in pots for small space gardening. Four to five-gallon plastic pots with holes drilled for drainage make an ideal setting for cannas. Generally, less fertilizer and water is used, and exposure to soil-dwelling insects and nematodes is greatly reduced. Potted cannas can be placed wherever you need them to brighten up a dull spot. They can actually be buried up to their rims to blend in with the landscape.
Besides dividing rhizomes, you can also grow cannas from seed. As cannas seeds have a tough seed coat, soaking them in warm water for twenty-four hours helps speed and increase germination. If the seeds are started early enough, you can actually get flowering sized plants this summer.
Cannas beds quickly get overcrowded and will need rejuvenation each year. Rejuvenation will allow for a clean-up of the bed and resetting of the best rhizomes. Dig up the clumps and clean out the old rhizomes. Look for vigorous rhizomes which contain viable eyes (sprouts). Clean the selected rhizomes and replant at once in the landscape or pots with enriched soil.
Selecting which cannas varieties to grow is a wide-open task. Keep in mind that there are two different kinds of flower types. Flowers arranged close together are called “gladiolus flowering” cannas. Classified as “orchid flowering” the other type of cannas has loosely arranged, narrow petals. Cannas are further classified into groups in consideration of their heights. Very Tall Growing cannas are sometimes called giant cannas. They are four feet tall and were first introduced in the 1950’s. Cultivars such as ‘Aida’, ‘La Boheme’ and ‘Madame Butterfly’ fit into this category and are named after operas. The next group is labeled as Low Growing which grows to about thirty-six inches. Good for gardens or containers, ‘Rosen Kavalier’, ‘Shell Pink’, and ‘Tiger Lily’ are several representatives of this cannas type. The smallest group of cannas is called Dwarfs and will grow to only about eighteen inches tall. These cultivars are named appropriately – ‘Doc’, ‘Grumpy’ and ‘Happy’.
Cannas rhizomes are available in most garden centers around our county. Seeds may have to be obtained through mail-order catalogs or through the Internet. For more information on all types of gardening questions, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays, and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer. Don’t forget to visit our other County Plant Clinics in the area. Please check this link for a complete list of site locations, dates and times – http://blogs.ifas.ufl.edu/charlotteco/files/2018/01/Plant-Clinics-Schedule.pdf .
Resources:
Tjia, B. & Black, R. J. (2003) Cannas for the Florida Landscape. The University of Florida Extension Service, IFAS.