Named after the German physician Johannes Thal, this is a great plant for a water garden. Plant in 12 to 18 inches of water over the crown or in 5 to 20-gallon tubs. Its native habitat of southeast asia includes cypress swamps, marshes, and ponds. Locating your plants in 18 to 24" of water during the winter months is sufficient. Cutting back and providing a thick layer of mulch will help the plant to winter well. If not possible, locate in a frost free location during the winter months. A greenhouse is ideal, protecting from frost and providing sufficient bright light. The entire plant is covered with a white powdery coating, thus the common names, Powdery Thalia and Powdery Alligator-flag. This powdery substance is water-repelling and also adds muted coloration, enhancing the plant's appearance. The petioles and basal sheath have internal air cavities, making them buoyant. After blooming, the flowers are replaced by smooth seed capsules, each containing 1 seed. Under the right conditions, the spreading rhizomes can create a quite large colony of plants. In locations where the correct growing conditions are absent, this plant is considered endangered. Hardy canna is a valuable plant for the environment. It goes through a natural process called Phytoremediation, which breaks down or removes excess pollutants from standing water. This improves the water quality. Insects, Diseases, and Other Plant Problems: No insect or disease issues.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; High Organic Matter; Loam (Silt)
Soil pH
Acid (<6.0); Neutral (6.0-8.0)
Soil drainage
Frequent Standing Water
Available space
3 feet-6 feet; 6-feet-12 feet; 12-24 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 3 ft. 0 in. - 6 ft. 0 in. | Width: 3 ft. 0 in. - 6 ft. 0 in.
Growth rate
Rapid
Maintenance
High; Medium
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Ascending; Erect
Texture
Medium
Foliage
Broadleaf Evergreen
Leaf color
Blue; Green
Leaf type
Compound (Pinnately , Bipinnately, Palmately)
Leaf arrangement
Other/more complex
Leaf shape
Elliptical; Lanceolate; Ovate
Leaf margin
Entire
Leaf feel
Smooth
Leaf value
Showy
Leaf size
> 6 inches long, > 6 inches wide
Hairs present
Yes
Leaf detail
The thick ovate to lancelolate blue-green leaves dusted with white powder are edged in purple and can grow up to 18" long. The upper leaf is pale green and hairless, while the underside is a greenish-white and has hairs. The hairs can be found along the base, central veins and margins. In daytime hours, the leaves are displayed in a horizontal position, but will come to attention in the evening, standing more erect.
Flower color
Purple/Lavender; White
Flower value
Showy
Flower form
Panicle
Flower size
< 1 inch
Flower detail
The small violet flowers that grow in pairs on 8 in. panicles are carried high above the foliage.
Bloom time
Summer
Fruit color
Brown/Copper; Purple/Lavender
Fruit type
Achene; Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Fruits are purple to brown utricles (similar to achenes), nearly globose to broadly obovoid with a single dark brown to black seed.
Stem color
Brown/Copper; Red/Burgundy
Stem detail
Like the other parts of this plant, a powdery substance covers the stems.
Wildlife & Ecology
Native status
Unknown
Origin
Southern US, Mexico
Distribution
Southeast Asia
Wildlife value
Larval food plant for the Brazilian Skipper butterfly. Also attracts butterflies, carpenter bees, bumblebees and hummingbirds. Ducks feed on the seeds.
Attracts
Bees; Butterflies; Hummingbirds; Pollinators; Small Mammals