Common Name: thalia
Type: Herbaceous perennial
Native Range: Southern United States, Mexico
Zone: 6 to 10
Height: 6.00 to 10.00 feet
Spread: 3.00 to 6.00 feet
Bloom Time: July to August
Bloom Description: Violet
Sun: Full sun
Suggested Use: Annual, Water Plant, Rain Garden
Grow in wet soils or in shallow water in full sun. Best in organically rich loams. Plants are considered winter hardy to USDA Zones 6-10. In St. Louis, plants are best grown in containers either sunk in wet mud near the water line or submerged in up to 2’ of water. Plants may also be grown in wet boggy areas. Containers covered by 18-24” of water will generally overwinter in place. Consider bringing other containers indoors to a greenhouse or other frost-free area with bright light. For plants grown in wet boggy soils, cut back tops and mulch heavily in winter.
Thalia dealbata, commonly called hardy water canna or powdery thalia, is a rhizomatous marsh or marginal aquatic perennial that features long-stalked canna like foliage and violet blue flowers. It is a tall plant (to 6-10’) that lends a tropical flavor to ponds and water gardens. It is native to swamps and ponds from South Carolina to Florida west to Missouri and Texas. It is rare to Missouri, its distribution being limited to swampy areas in the southeastern lowlands region. Features paddle-shaped to lanceolate-elliptic blue-green canna-like leaves (to 18” long) on petioles to 24” long. Foliage is dusted with white powder. Violet flowers appear in branched open panicles (to 8” long) atop scapes typically rising well above the foliage to 6’ (less frequently to 10’) tall. Blooms July and August.
Genus name honors Johannes Thal (1542-1583), German physician.
Specific epithet means whitened or covered with a white powder.
No serious insect or disease problems.
Margins of ponds, pools and large water gardens. Bog gardens.