These are beautiful, hardy and tender, aquatic perennials. The long-stalked leaves grow directly from the ground and they produce branching spikes of flowers in the summer. Thalia dealbata, the Powdery Thalia, is a hardy kind found growing wild from South Carolina to Florida to Texas. In can be grown outdoors throughout the year except for in very cold climates; it should then be wintered doors. The Powdery Thalia can grow up to 6 feet high. It produces handsome, ovate to lance-shaped, blue-green leaves with purple margins that grow up to 20 inches long and 10 inches wide. They are lightly coated with white powder, thus its common name. Branched panicles, up to 8 inches in length, are topped with small, violet flowers. S. geniculata var. ruminoides, the Red-stemmed Thalia, is a tropical kind native to the West Indies. It resembles Thalia dealbata, except it has pretty dark red stems. In tropical climates, it grows 5 or 6 feet high, but can grow up to 8 feet. Its lavender flowers grow high above the foliage.

Plant in 5- to 20-gallon containers filled with light, rich loam. Thalia dealbata can be grown in water up to a foot over the crown. Thalia geniculata var. ruminoides can have 1 to 6 inches of water covering the crown. They should be grown in sun or partial shade, in a location sheltered from harsh winds. In cold climates, they should be wintered indoors as a tropical houseplant.

These plants may be divided in the spring or summer, or cold, moist stratified seeds may be sown. When dividing, hose the soil from the compact, mat of roots to reveal the knobby, rhizomatous growth that can be divided. Separate into pieces that have rhizomes and leaves.

Thalia dealbata;
Thalia geniculata & var. ruminoides.