Thalia dealbata (Powdery Alligator Flag or Powdery Thalia) is a bold native aquatic perennial prized for its dramatic blue-green foliage and tall spikes of violet flowers. Its large, paddle-shaped leaves are coated with a distinctive powdery white bloom that gives the plant its common name and creates a striking contrast along pond edges and wetlands. Blooming throughout the summer, the nectar-rich flowers attract bees, butterflies, and other pollinators while dense stands provide cover for aquatic wildlife. With its tropical appearance and impressive height, this standout species adds structure, movement, and habitat value to ponds and water gardens.

Scientific Name: Thalia dealbata

Origin: Texas and the Southern United States

Native Habitat: Marshes, ponds, swamps, wetland margins

Height: Up to 8 feet tall

Spread: Variable (spreads by rhizomes)

Light: Full Sun to Part Shade

Water: Shallow Water or poorly drained, wet soils

USDA Zones: 6–11

Bloom: May to October