Canna lilies are vibrant, tropical-looking plants known for their bold foliage and striking flowers, making them a popular choice for gardens and landscapes. This guide provides detailed information on successfully growing and caring for these impressive plants.
Meet the Canna Lily
Canna lilies are herbaceous perennials with large, showy flowers and broad, paddle-shaped leaves, adding a tropical aesthetic to any garden. Often mistaken for true lilies, cannas are unrelated, belonging to the family Cannaceae and sharing closer ties with ginger and bananas. Originating from the American tropics, varieties showcase diverse leaf colors, including green, bronze, maroon, and variegated patterns. Their vibrant flowers bloom in shades of red, orange, yellow, pink, white, and various combinations, emerging from an underground rhizome.
Canna Lily Care Essentials
Sunlight
Canna lilies require specific care to produce abundant blooms and maintain lush foliage. Consistent sunlight is important; they perform best with at least six to eight hours of direct sun daily. While partial shade is tolerated in hotter climates, insufficient light results in leggy growth and reduced flower production.
Moisture
Consistent soil moisture is important for canna lilies, as they prefer continuously moist conditions without being waterlogged. Deep watering once or twice a week is sufficient, though hotter periods or container-grown plants may need more frequent checks. Good drainage is essential to prevent root issues, even with their preference for moisture.
Nutrients
Canna lilies are heavy feeders, requiring nutrient-rich soil for vigorous growth and prolific flowering. They flourish in fertile, well-draining soil rich in organic matter. Amending the soil with compost before planting improves its structure and fertility. Regular fertilization throughout the growing season supports healthy development and bloom production. A balanced, slow-release fertilizer applied at planting, followed by liquid feeds every four to six weeks, provides necessary nutrients. Avoid over-fertilizing with high-nitrogen products, as this promotes excessive foliage at the expense of flowers.
Planting Canna Lilies
Proper planting techniques ensure successful establishment. Canna lilies are sensitive to cold and should only be planted outdoors after the last spring frost and when soil temperature consistently reaches at least 60°F (15°C). This often coincides with tomato planting time.
Before planting, prepare the site by loosening the soil to a depth of 8 to 12 inches and incorporating 2 to 4 inches of compost to enhance fertility and drainage.
Position rhizomes horizontally in prepared holes with their “eyes” or growth points facing upwards. The planting depth is 2 to 4 inches below the soil surface. Space rhizomes 12 to 24 inches apart, depending on the variety’s mature size, to allow for adequate growth and air circulation.
After placing rhizomes, cover them with soil and gently firm it down. Initial thorough watering settles the soil, but withhold further watering for up to three weeks until new growth emerges.
Overwintering Canna Lilies
In colder climates (USDA Zones 3-7), canna lilies are not hardy. Their rhizomes require protection from freezing temperatures for survival. After the first hard frost causes foliage to die back, prepare rhizomes for winter storage.
Cut stems and foliage back to 4 to 6 inches above ground. Carefully dig up the entire clump of rhizomes, avoiding damage. Shake off excess soil.
Allow rhizomes to dry or “cure” in a warm, dry, well-ventilated location for several days to a week. This toughens their outer skin and prevents rot during storage.
Store cured rhizomes in a cool, dark, dry place (40-55°F / 4-12°C). Use peat moss, vermiculite, or sawdust as storage mediums to absorb moisture and maintain humidity. Ensure rhizomes do not touch to minimize rot spread. Periodically check them throughout winter, misting lightly if shriveled, but avoiding excessive moisture.
Common Canna Lily Problems
Pests
Canna lilies are generally robust, but can encounter issues impacting their health. Pests like canna leaf rollers, spider mites, aphids, and slugs can damage foliage. Leaf rollers cause leaves to appear chewed or rolled. Regular inspection helps early detection; a strong water spray can dislodge many soft-bodied pests.
Diseases
Fungal diseases, such as canna rust, are identifiable by small, orange, powdery spots on leaves and stems, especially in wet, humid conditions. Canna mosaic virus is another issue, causing leaf deformities, streaking, and mottling. Proper garden hygiene, including removing affected foliage and controlling sap-sucking insects, helps manage disease spread.
Environmental Factors
Environmental factors can also lead to problems. A lack of blooms indicates insufficient sunlight or nutrient deficiencies. Yellowing or browning leaves signal watering issues (too much or too little) or nutrient imbalance. Ensuring appropriate light, consistent moisture, and adequate fertilization addresses many common non-pest or disease-related problems.