Three-Square

Schoenoplectus pungens

USDA, NRCS. 2018. The PLANTS Database (http://plants.usda.gov, 28 March 2018). National Plant Data Team, Greensboro, NC 27401-4901 USA.
Illustration courtesy of University of Florida/IFAS Center for Aquatic and Invasive Plants. Used with permission.

What is Three-Square?

Physical Characteristics

Leaves:

• 2-4 leaves

Scales:

• Brown in color
• 0.16-0.2 inches long
• Well-marked midnerve

Flowers:

• 28-50 flowers

Spikelets:

• 1-4 spikelets
• Immobile
• 0.28-0.67 inches long
• 0.16-0.2 inches thick
• Oval- or sword-shaped

Fruit:

• One seed
• Does not open to release seed when ripe
• 0.09-0.13 inches long
• 0.08-0.09 inches wide
• Flat or slightly bulging
• Smooth
• Dark brown in color when ripe

Stem:

Rhizomes:

• Creeping
• Reddish-brown in color
• 0.08-0.13 inches thick

Hollow Stems:

• Growing upward
• 0.75-5 feet long
• 0.08-0.23 inches thick

Where Does it Grow?

Three-square can be found in low, moist, often alkaline ground, in water, and around seepage areas.

Pros and Cons of Three-Square

Seeds are consumed by ducks; while geese, muskrats, and nutria consume the rhizomes. Submerged portions of all aquatic plants provide habitats for many micro and macro invertebrates. These invertebrates in turn are used as food by fish and other wildlife species (e.g. amphibians, reptiles, ducks, etc.). After aquatic plants die, their decomposition by bacteria and fungi provides food (called “detritus”) for many aquatic invertebrates.