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Native Plant Society of Texas

Powdery Thalia

Thalia dealbata

Other common name(s):

Powdery Alligator-flag, Water Canna

Family:

Marantaceae (Arrowroot Family)

Plant Ecoregion Distribution Map

This map uses data from the US EPA. EPA  servers have been offline frequently so maps may not display. We are working on a solution.

East Central Texas Plains, Gulf Coast Prairies and Marshes, Western Gulf Coastal Plain
Northern Post Oak Savanna, Southern Post Oak Savanna
Northern Humid Gulf Coastal Prairies
Flatwoods, Floodplains and Low Terraces3, Pleistocene Fluvial Terraces, Red River Bottomlands, Southern Tertiary Uplands

Plant Characteristics

Growth Form

Wetland

Height

3
to
8
ft.

Spread

1
to
2
ft.

Leaf Retention

Deciduous

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Shallow, Poor Drainage, Moist, Mud, Saline

Light Requirement

Part Shade

Water Requirement

High

Native Habitat

Wetland or Riparian

Bloom and Attraction

Bloom Color

White, Purple

Bloom Season

Spring, Summer, Fall

Seasonal Interest

Larval Host

Wildlife Benefit

Butterflies

Maintenance

Native habitat: Cypress swamps, marshes, and ponds. Good in water gardens, bogs, or pond areas. It prefers shallow water typically ranging from a few inches to a foot deep. Set up a water collection tank near a downspout to supplement water. Propagation: clump division.

Comments

Blooms May-October. Large, broadly lance-shaped, long-stemmed leaves. All parts of plant covered with a white powdery coating. The flowers are crowded in an open panicle. The fruit is a capsule. Larval host: Brazilian Skipper.
Previous Scientific Name(s): Thalia barbata

References

Learn about how to propagate Texas native plants.

Material Treatment Method Collection References
Clump Division Carefully separate the rhizomes into smaller sections, ensuring each section has roots and shoots, and replant them in moist or submerged conditions. Can be done in early spring or autumn. 1) https://www.lincsplants.com/products/thalia-dealbata-powdery-alligator-flag-or-hardy-water-canna-marginal-pond-plants-pond-plants-water-plants-mp114#:~:text=Propagation%20and%20Care,the%20soil%20remains%20consistently%20wet. 2) https://earthone.io/plant/thalia%20dealbata
Seed Stratification Seeds can be sown in spring, but germination may be slow. Clean seeds by rubbing them over a roughened surface (use an old radiator screen from a tractor) to remove the papery fruit coverings, which are then blown away. Seeds can be stored dry in zip-lock-type plastic bags for at least 6 mo. Post-harvest storage in a moist medium (a wet paper towels and sphagnum peat moss for experimental purposes, however, other media would probably be acceptable) at 5.5 øC (42 øF) works well. The cool temperatures and moist conditions serve as a stratification process. best germination (15% to 35% after 9 to 12 wk) on moist growing medium after either stratifying dry-stored seeds or keeping seeds in moist storage. Greenhouse temperatures range from 13 to 38 øC (55 to 100 øF) during the germination period. I maintained moist medium by regularly watering containers situated on normal greenhouse benches. Collect seeds when fully mature and before any significant shattering occurs, usually late August through mid September. Shake the fruit clusters over a container. 1) https://www.lincsplants.com/products/thalia-dealbata-powdery-alligator-flag-or-hardy-water-canna-marginal-pond-plants-pond-plants-water-plants-mp114#:~:text=Propagation%20and%20Care,the%20soil%20remains%20consistently%20wet. 2) https://npn.rngr.net/renderNPNProtocolDetails?selectedProtocolIds=marantaceae-thalia-467&referer=wildflower#:~:text=Propagule%20Collection:,serve%20as%20a%20stratification%20process.

About the Region

Fall Symposium 2025 Logo - Teach for the Future

Salado, the location of our Fall 2025 Symposium, lies at the intersection of two ecoregions: the Edwards Plateau (Limestone Cut Plain) and Blackland Prairie (Northern Blackland Prairie).

The Edwards Plateau area is also called the Hill Country; however, this general term covers a much larger area extending farther north. Spring-fed creeks are found throughout the region; deep limestone canyons, rivers, and lakes (reservoirs) are common. Ashe juniper is perhaps the most common woody species found throughout the region. Additional woody species include various species of oak, with live oak (Quercus fusiformis) being the most common. Sycamores (Platanus occidentalis) and bald cypress (Taxodium distichum) border waterways. This area is well known for its spring wildflower displays, though they may be viewed in spring, late summer, and fall, as well. According to Texas Parks and Wildlife, average annual rainfall in the Edwards Plateau ranges from 15 to 34 inches.

The Blackland Prairie extends from the Red River south to San Antonio, bordered on the west by the Edwards Plateau and the Cross Timbers, and on the east by the Post Oak Savannah. Annual rainfall averages 30 to 40 inches, with higher averages to the east. This region is dominated by prairie species. The most common grass species include little bluestem (Schizachyrium scoparium) and Indian grass (Sorghastrum nutans) in the uplands and switchgrass (Panicum virgatum) in the riparian areas and drainages. Common herbaceous flowering plants include salvias, penstemons, and silphiums. This area has suffered greatly from overgrazing and agricultural use. Few intact areas remain, though many of the plants can be found along county roadsides throughout the region.

Our fall Symposium host chapter, the Tonkawa Chapter, includes both of these ecoregions.

Source: Wildflowers of Texas by Michael Eason