Canna lilies, with their vivid flowers and broad, colorful foliage, bring a touch of the tropics to any setting. While commonly seen flourishing outdoors, these striking plants can also thrive indoors, offering their exotic beauty year-round.
Feasibility of Growing Canna Lilies Indoors
Growing canna lilies indoors is possible, allowing them to thrive even in colder climates. Native to tropical regions, these rhizomatous perennials adapt well indoors when their specific needs are met. Indoor cultivation extends their growing season, allowing continuous blooms through colder months, unlike outdoor plants that go dormant. This provides a continuous display of lush foliage and exotic flowers, transforming interior spaces into tropical havens.
Success hinges on replicating their preferred warm, bright, and humid conditions. While outdoor plants are often larger, indoor cannas can still reach 2 to 5 feet, depending on the variety.
Essential Care for Indoor Canna Lilies
Light Requirements
Indoor canna lilies require abundant direct sunlight for vibrant blooms. A south or west-facing window is ideal, providing several hours of strong light. At least six hours of direct sunlight daily is needed for optimal growth and flowering. Insufficient light leads to tall, leafy plants with few or no flowers.
If natural light is insufficient, especially in winter, supplemental grow lights can provide the necessary spectrum. Regular rotation ensures even growth. Adjusting its position seasonally supports health and blooming.
Watering Practices
Canna lilies are water-loving plants requiring consistent moisture. Keep soil consistently moist but never waterlogged, as this can lead to rhizome rot. Watering once or twice weekly is a guideline, but frequency depends on temperature, humidity, and pot size.
Check soil moisture regularly; the top few inches should feel crumbly and moist before rewatering. Allowing the pot to dry completely can signal dormancy, hindering growth. Consistent watering during active growth supports robust development and continuous flowering.
Soil and Potting
Appropriate soil and pot selection is important for indoor canna lilies. A rich, well-draining potting mix, often amended with organic matter like compost, is ideal. Good drainage is paramount to prevent waterlogging and harm to rhizomes. While some sources previously suggested adding pebbles to the bottom of pots for drainage, this is not effective and can impede water movement; instead, rely on ample drainage holes.
Cannas develop extensive root systems and grow tall, so a large, sturdy pot is beneficial. A container at least 12 inches in diameter is recommended for ample root space and plant stability. Ceramic, terra-cotta, or durable plastic pots with drainage holes are suitable.
Temperature and Humidity
Cannas prefer warm conditions and are sensitive to cold temperatures and frost. They thrive in temperatures from 59°F to 100°F (15°C to 38°C). Maintaining indoor temperatures above 60°F (15°C) promotes continuous growth and potential winter blooming.
High humidity also benefits cannas. To increase indoor humidity, various methods can be used:
Misting leaves daily with filtered water.
Grouping plants together to create a humid microclimate.
Placing the pot on a pebble tray filled with water (ensure water does not touch the pot’s base) for gradual evaporation.
Using a humidifier to raise ambient humidity.
Fertilization
Cannas are heavy feeders and benefit from regular fertilization for vigorous growth and prolific flowering. During the active growing season (spring through fall), apply a balanced, slow-release granular fertilizer or liquid feed. A phosphorus-rich fertilizer (e.g., 5-10-5 blend) can encourage stronger roots and more abundant blooms.
Fertilize monthly, or at least twice during the growing season (early spring and mid-summer). For indoor plants, a common approach is half-strength liquid fertilizer every two to three weeks, or full-strength once a month. Mixing compost into the potting mix or using dilute fish/seaweed emulsion can also provide beneficial micronutrients.
Planting Canna Lilies for Indoor Growth
Planting canna lilies indoors begins with selecting healthy rhizomes. Plant healthy rhizomes in a large container (at least 12 inches in diameter) with adequate drainage holes to accommodate their robust root system. A rich, well-draining potting mix, often enhanced with organic matter, is essential.
To plant, fill the pot with potting soil, leaving a few inches from the rim. Position the rhizome horizontally, or with any visible “eyes” facing upward, about 4 to 5 inches deep. Cover with soil and gently pat down. After planting, water thoroughly to help the soil settle and provide initial moisture. Consistent moisture and a warm, sunny location will encourage sprouting and new growth.
Overwintering Outdoor Canna Lilies Indoors
For canna lilies grown outdoors in regions with cold winters (USDA zones below 7-10), overwintering them indoors protects their rhizomes from freezing. After the first fall frost, which causes foliage to die back, prepare them for indoor storage. Cut plant stalks back to a few inches above soil level.
Carefully dig up rhizome clumps, avoiding damage. Shake off excess soil and air dry rhizomes in a warm, dry place for several days; this curing prevents rot and mold during storage. Once cured, store rhizomes in a cool, dark, dry location (e.g., basement, garage, cellar) where temperatures remain between 40°F (4°C) and 50°F (10°C).
Place them in a paper bag, newspaper, or a box surrounded by slightly damp peat moss or vermiculite to maintain moisture without promoting rot; ensure rhizomes do not touch. Periodically check for drying, rot, or mold; mist lightly if too dry and remove affected parts. In spring, once frost danger passes and outdoor temperatures warm, replant the rhizomes.