Canna Plant Profile (Canna Lily)
Cannas are generally planted for their foliage alone, despite their striking flowers. The huge, paddle-like leaves are variegated and striped and occur in a variety of greens and blue greens. Canna flowers are tubular and lily-like, and they bloom on tall stalks bursting out of the foliage in hues and combinations of yellow, orange, red, and pink. Rhizomes planted after the final frost in the spring will take a few weeks to sprout, but once they do, they will develop quickly and may even flower the first year.
Cannas are rarely classified and are classified as hybrids because most Cannas available today are the result of multiple crossings.
Canna Plants: How to Grow Them
Cannas will repeat-bloom throughout the summer in planting zones 8 and up, and throughout the year in planting zones 9 and above. There are three possibilities for everyone else: let them die off each fall and start fresh rhizomes in the spring; container the plants and bring them indoors to live as houseplants, or dig out and store the rhizomes for the winter (and replant them in spring).
Insects and diseases are rarely a problem for cannas. Their leaves have a waxy coating that repels water and protects them from disease. Although there are few pest concerns, grasshoppers and caterpillars may eat the leaves.
Cannas thrive in direct sunlight. This means that they may require more water in scorching locations, yet they need heat to flourish. In the warmest part of the day, adding afternoon shadow extends the life of the flowers.
Cannas should be planted in fertile, moist soil with a slightly acidic to neutral pH.
Cannas require regular watering and evenly moist soil. Water frequently, especially in hot weather. The leaves will tear or fracture if there isn't enough water.
Humidity and Temperature
The time it takes for flowers to bloom is determined by the climate and weather. Plants may take longer to get started in locations with chilly springs. They will blossom earlier if you pot them up indoors before the final frost date and move them out while they are still growing. Cannas, being tropical plants, like humid air but may endure relative dryness if properly watered.
Cannas are thirsty plants that require a lot of water, although they store some food in their rhizomes. Feed them with a balanced fertilizer in the early spring and late summer.
Canna Plant Propagation
Canna lilies are usually grown from rhizomes rather than seeds because most of the newer kinds are hybrids. Cut the foliage and stem to 6 inches if you live in a frosty climate and want to keep your outdoor plants for the next season. Then dig the rhizomes and set them aside to dry in a shaded, protected location. When the rhizomes are dry, shake off any extra soil, cover them in a newspaper, and keep them in the dark, cool place until spring. Check them regularly to ensure that they are not rotting or drying out.
The number of "eyes" on a rhizome is related to the size and quantity of canna blossoms. The larger the plant and the better the blossoms, the more eyes it has. Look for rhizomes with 3-5 eyes and plant them 4 to 5 inches deep in the spring with the eyes pointing up. Alternatively, if you want to get a jump on the season, plant them up indoors four to six weeks before the last frost and move them out as the weather warms. Keep the rhizomes damp but not drenched.
Varieties of Cannas
- 'Lucifer': 2 feet tall, crimson blooms with golden edges, green leaves
- 'The President': 3 to 3.5 feet tall, crimson blooms, green leaves
- 'Pretoria' ('Bengal Tiger'): 4 to 6 feet tall, orange blooms, yellow and green striped foliage
- 'Stuttgart': 3 to 4 feet tall with orange flowers and green and white variegated leaves.
- 'Tropicanna': dark variegated foliage with huge, orange flowers; also available in Black and Gold; grows 4 to 6 feet tall.
Deadhead your plants when the blooms fade to maintain them flowering throughout the season. You can cut back the flower stalks before they bloom if you only want to grow cannas for their leaves.
Uses in the Landscape
Cannas can't help but be the center of attention. A single specimen can anchor a circle garden. When grouped, they can have a tropical or Victorian appearance. The tropical colors and mood go well with other "hot" colors.
There's even a canna kind that thrives in excessively damp soil, such as in water gardens. This plant is a Canna glauca hybrid. They look great in bog gardens and can also be used in water gardens in baskets.