Cannas are elegant colorful tropical flowers that are easy to grow and pretty darn rugged! Here’s how to grow them.
About cannas
History:
Cannas are tender plants from tropical regions of the world but are easy to grow outdoors in many areas providing there is no risk of frost. They were very popular in the Victorian garden for their elegant tropical look and landscape ease. Then in many parts of the country, particularly sunny California and Florida, they became popular as city landscape plants in road medians, traffic circles and public gardens. Now they are making a come back with home gardeners who want a taste of the tropics from an easy care flowering plant–there is a canna for every taste! They range in height from 2 1/2 feet (dwarf or Opera series types) to 16′ the Omega) The dwarfs only grow to 3′ and tend to have larger flowers. The average tall canna is 4-6′. Foliage colors vary from green to purple to bronze and varigated yellow and green or even red orange with colorful flowers of pale or lemon yellow, scarlet or ruby reds, salmon or hot pinks, orange and multi-colored spotted or striped.
Gardening Tips: Grow Tropical Cannas – in Pots!
Cultivation:
Cannas can be grown in pots, windowboxes and the ground. They make great landscaping plants to fill in large areas as they multiply each year and can form a screen or windbreak, but if you don’t want them to spread, sink pots into the ground. They prefer full sun and can take lots of rain. They aren’t fussy about soils but are big feeders I am told. They do like soil enriched with organic matter and dressed with a general fertilizer such as Miracle Grow. I add coffee grounds, egg shells, and shredded leaves regularly and sometimes Breck’s Dutch Bulb Treat 5-10-5 a couple times a year but it isn’t necessary. Cannas do well with other plants and can be underplanted with annuals, perennials, vines or shrubs. I find ferns, sedums and aloes look good, attracting and holding the moisture they adore. I like combining colors and textures– chartreuse sedums and black leaved peppers, coleus, and even trailing vines. Some cannas grow well in water too. The ideal temperature is 60F but cannas will grow at much higher or lower temperatures provided they do not get frost. Cannas make good container plants for the patio or sunroom. They don’t mind crowding but plant in good sized pots (10″) and windowboxes using a good potting compost, water and feed regularly. In a greenhouse, if temperatures are kept at 55F or above, cannas can grow and flower all year, just dead head old flowered stems from time to time– cut them off conservatively just below the last bloom as they often shoot out more flowers! Divide in spring or fall when they are more likely to be dormant. Many cannas like the Bengal Tiger, Tropicana and purple leaved varieties like Black Knight and Wyoming look beautiful even without blooms because of their colorful foliage. (More about these in upcoming aticles.)
Maintenance:
During the growing season, keep the plants well watered and for maximum growth, use a liquid feed. Mulch also helps hold in moisture but if you underplant, you will have attractive living mulch! Dead-heading prolongs the display and keeps the plants looking tidy. Remove dead blooms and yellow or brown leaves and shred for mulch. Be sure not to remove the side-shoots below the first flowers, as these become subsequent blooms. Most cannas do not need staking.
Pests: Very few pests bother my cannas. If slugs are a problem throw some pennies in the soil with broken eggshells. Beer placed in shallow dishes or film canisters attracts them as well and they drown. Few other pests or diseases attack cannas but occasionally small caterpillers or “leaf rollers” may cause damage that is easily confused with slug damage. The leaves will be rolled and sticky and often have a few distinct holes in them. Remove and consult a local nursery for the best remedies.
After Summer:
At the end of the season, make sure the plants are carefully labelled before the blooming ends or you may get confused over colors and varieties! I do! In colder climates, you may want to bring the pots indoors to a sunroom or near windows before that first frost. If they are in the ground, as soon as frosts blacken the foliage, dig up the rhizomes and store in frost free conditions such as a garage or cellar. You can pack the roots into peat or newspaper to keep them moist. Do not allow the roots to dry out completely or they may shrivel up and die. In green all year climates like mine, I leave them in the pots and cut back on water but would never leave them outside for a freeze. I put them under row covers or in the back porch under sheets and blankets. Cannas can be left in the ground permanently in some places, covered with a thick mulch to protect from frost before winter. Overwintered plants may be divided in spring but do not rush it. To divide them, wait til they put forth new shoots and easily break apart. Pot in any good potting soil in a 6″ or larger pot. When I pull mine apart and they aren’t dormant I stick them in water and they keep for a long time.
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