Thalia Species, Powdery Alligator-Flag, Powdery Thalia, Water Canna

Thalia dealbata

Family: Marantaceae
Genus: Thalia (THAL-ee-uh) (Info)
Species: dealbata (day-al-BAH-tuh) (Info)
Synonym:Thalia barbata


Ponds and Aquatics

Water Requirements:

Very high moisture needs; suitable for bogs and water gardens

Sun Exposure:

Sun to Partial Shade


Unknown - Tell us

Foliage Color:



4-6 ft. (1.2-1.8 m)


6-8 ft. (1.8-2.4 m)


USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

Where to Grow:

Unknown - Tell us


Unknown - Tell us

Bloom Color:

Medium Purple

Bloom Characteristics:

Unknown - Tell us

Bloom Size:

Unknown - Tell us

Bloom Time:

Late Summer/Early Fall

Other details:

Unknown - Tell us

Soil pH requirements:

Unknown - Tell us

Patent Information:


Propagation Methods:

By dividing rhizomes, tubers, corms or bulbs (including offsets)

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds


This plant is said to grow outdoors in the following regions:

Mesa, Arizona

Melbourne, Florida

Niceville, Florida

Orlando, Florida

Punta Gorda, Florida

Dallas, Georgia

Chicago, Illinois

Coushatta, Louisiana

Mandeville, Louisiana

Centreville, Maryland

Silver Spring, Maryland

Holland, Massachusetts

Dearborn Heights, Michigan

Minneapolis, Minnesota

Mount Vernon, Missouri

Saint Louis, Missouri

Averill Park, New York

Cincinnati, Ohio

Hulbert, Oklahoma

Bensalem, Pennsylvania

Houston, Pennsylvania

Norristown, Pennsylvania

Conway, South Carolina

Summerville, South Carolina

Loretto, Tennessee

Flower Mound, Texas

Harlingen, Texas

Mansfield, Texas

show all

Gardeners' Notes:


On Apr 17, 2012, Saltydoc from Silver Spring, MD (Zone 7a) wrote:

I love this plant in my pond. However, it has escaped the pot and is growing throughout the pond (stones over lining). I'm afraid the roots will go through the liner. They are well anchored when I tried gentle pulling, and I'm afraid to yank them in case they tear the liner. Any suggestions? The pond is a water lily and lotus pond with goldfish and koi, around 1200 gallons with a waterfall and stream. Thanks.


On Feb 14, 2011, dakota1sam from Saint Louis, MO wrote:

This plant is so beautiful and the hummingbirds love it. The only problem I had was during strong wind it would fall over alot, but repotting it in a larger pot took care of this . It has overwintered in the pond here in st. Louis with only a deicer. I collected some seeds last fall and I am going to attempt germinating them this spring.


On Aug 11, 2010, Malus2006 from Coon Rapids, MN (Zone 4a) wrote:

It dislike shade of any kind for me and didn't overwinter well indoor.


On Aug 11, 2009, ethnicnutter from Norwich,
United Kingdom wrote:

Thalia grows well in my pond in Norfolk U.K. Has anyone else noticed that it seems to trap flies in the flower, they take about a day to die, if touched whilst still alive they move side to side but cannot free themselves. After another two days the abdomen is as thin as paper. I cannot find any record of them being a carnivorous. I have put a photo of flower and insects on the site.


On Jul 12, 2008, MOJB from Norristown, PA wrote:

My mother bought a small piece of this plant and put it in her koi pond where it grew like crazy (good crazy). She overwintered it in her (Zone 6) pond with a small heater in there for the past two seasons successfully. If you want to test overwintering it in your pond it would be easy to just divide it and leave part of it in the pond with the heater(/de-icer) so you won't lose the entire plant if it doesn't work the first time.

It has grown so large after two seasons of overwintering that my mom had to divide the (originally tiny) plant and she gave me a 3 ft by 3 ft section of it this year. It's currently in a large pot that I filled with soil (with water saving crystals) and didn't drill any drainage holes into. Even small brown (dead-looking) pieces that fell off wh... read more


On Nov 22, 2005, remydog from Westwood, MA wrote:

We live outside of Boston, MA and just purchased this plant in the spring for our koi pond. Fantastic! Very prolific and the slender flower stalks tower over everything.

Being in zone 5-6, I am curious if I can leave this in the pond to overwinter. I have been told that some people move them to deep water and they do fine. Others bring them in. Being so tall, it is dominating my dining room and I would prefer to leave it in the pond if that will not kill it.



On Sep 7, 2004, shearpamela from Flower Mound, TX (Zone 7b) wrote:

Easy to grow and very pretty purple blooms that last a long time.


On Oct 21, 2002, twnleaf wrote:

We are growing this at a high elevation in zone 7. The thalia bloomed at periods around 74 degrees this year. Appeared to not bloom at hot periods. Grown in full sun in water 8 inches over the top of soil level. The blooms are delicate so do not touch those as they will drop, but do not seem to be disturbed by hummingbirds. If the blooms are disturbed you miss your chance for the wonderful skin covered seeds in Fall. Those appear to be purple berries but within three weeks after picking they dry so as to remove the skin easily. Seeds are prone to mildew while fresh after picking lightly wash with a antifungicidal in a portion of water. The seeds after shelled appear to have a marbled coloring kind of like a pinto bean. The seeds should be rounded not sunken. To use seeds the next spring, s... read more


On Aug 13, 2001, JJsgarden from Northern Piedmont, NC (Zone 7b) wrote:

Thalia dealbata

Suitable plant for bog or pond. The leaves are lance-shaped, bluish green with purple margins. The leaves can grow to 20" long and 10" wide and are covered with a white powder, thus, the common name of Powdery Thalia.

These plants require a large pot of at least a 5 gal. size or larger. They can be grown in water up to 12" over the pot rim.

Sun to partial shade, but shelter from strong winds to keep from tipping over. In cold climates, they may be overwintered indoors as a tropical houseplant.

In the summer, Thalia has tall spikes of tiny purple flowers.