Growing cannas in your garden is an easy way to create instant tropical flair. Cannas are tropical and subtropical flowering plants with large, banana-like leaves. Cannas' popularity and active hybridizing have resulted in a dazzling array of cannas to choose from, many with large, showy flowers and variegated leaves that look like stained glass when the sun shines through them.
Striking flowers notwithstanding, cannas are often grown for their foliage alone. The large, paddle-like leaves come in a range of greens and blue-greens and can have variegation and stripes. Somewhat tubular and lily-like, Canna flowers come in shades and combinations of yellow, orange, red, and pink and are borne on tall stalks poking out of the foliage. Rhizomes planted in spring after the last frost will take a few weeks to sprout but will then grow at a rapid pace and may even flower in the first year.
Because most Cannas sold today are the result of many crosses, Cannas are rarely classified and are simply considered hybrids.
|Botanical Name||Canna × generalis|
|Common Name||Canna lily|
|Plant Type||Annual flower (in most zones)|
|Mature Size||18 inches to 10 feet tall and 1.5 to 6 feet wide|
|Sun Exposure||Full sun|
|Soil Type||Rich, moist|
|Soil pH||6.0 to 6.5|
|Flower Color||Yellow, orange, red, pink|
|Hardiness Zones||8 to 11|
How to Grow Canna Plants
In planting zones 8 and up, cannas will repeat-bloom throughout summer, and throughout the year in zones 9 and above. For everyone else, there are three options: You can let them die off each fall and start with fresh rhizomes in the spring; you can pot the plants and bring them indoors to live as houseplants; or you can dig up and store the rhizomes for the winter (and replant them in spring).
Cannas are not often bothered by insects or disease. Their leaves are covered with a waxy substance that repels water and protects against fungus. Pest problems are minimal, but grasshoppers and caterpillars may munch on the leaves.
Cannas do best in full sun. This means they may need more water in really hot climates, but they need heat to spur their growth. In the hottest area, some afternoon shade helps flowers last longer.
Cannas need consistent water and evenly moist soil. Water often, especially in extreme heat. Insufficient water will cause the leaves to tear or crack.
Temperature and Humidity
Blooming depends on the climate and weather. In areas with cool springs, the plants may be slow to get started. Potting them up indoors, before your last frost date, and moving them out while they are already growing, will help them bloom earlier. As tropical plants, cannas prefer humid air but can tolerate relative dryness, especially if they are properly watered.
In addition to needing lots of water, cannas are hungry plants, although they store some food in their rhizomes. Feed them in early spring and midsummer, using a balanced fertilizer.
Propagating Canna Plants
Since most of the newer varieties are hybrids, canna lilies are generally grown from rhizomes rather than seed. If you live in a climate with frost and would like to preserve outdoor plants for the next season, cut the foliage and stem to 6 inches. Then, dig the rhizomes and let them dry in a protected, shady spot. When dry, shake off the excess soil, wrap the rhizomes in newspaper, and store them in a dark, cool location until spring. Check on them periodically to make sure they are not rotting or drying out.
The size and amount of blooms of cannas are linked to the number of "eyes" on a rhizome. The more eyes, the bigger plant and better blooms. Look for rhizomes with 3-5 eyes, and plant them in spring with the eyes facing up 4 to 5 inches deep. Or, if you'd like to get a head start on the season, pot them up indoors, four to six weeks before your last frost, and move them out once the temperature warms. Keep the rhizomes moist but not soaking wet.
Varieties of Cannas
- 'Lucifer': red flowers with yellow borders; green leaves; 2 feet tall
- 'The President': scarlet blossoms; green leaves; 3 to 3.5 feet tall
- 'Pretoria' ('Bengal Tiger'): orange flowers; yellow and green striped foliage; 4 to 6 feet tall
- 'Stuttgart': orange flowers; green and white variegated foliage; 3 to 4 feet tall
- 'Tropicanna': dark variegated leaves with large, orange flowers; also comes in Black and Gold; 4 to 6 feet tall
To keep your plants flowering throughout the season, deadhead them as the blooms start to fade. If you prefer to grow cannas for their foliage alone, you can cut back the flower stalks before they even have a chance to bloom.
Cannas can't help but be focal points. A single specimen can anchor a circle garden. Planted in a mass, they can look both tropical and Victorian. The colors and tropical feel combine well with other "hot" colors.
There's even a variety of canna that grows in extremely wet soil--or even in water gardens. This plant is a hybrid of Canna glauca. They look gorgeous in bog gardens, or can be planted in baskets in water gardens.