Common Threesquare: A Hardy Native Sedge for Wet Areas
If you’re looking to add some authentic North American charm to your wetland garden or rain garden, let me introduce you to common threesquare (Schoenoplectus pungens var. pungens). This unassuming but incredibly useful native sedge might not win any beauty contests, but it’s a workhorse that deserves a spot in the right landscape.
What Makes Common Threesquare Special?
Common threesquare is a perennial sedge that’s as American as apple pie – and then some! This hardy graminoid (that’s fancy talk for grass-like plant) is native across a huge swath of North America, from coast to coast and border to border. You’ll find it naturally growing everywhere from Alabama to Saskatchewan, making it one of our continent’s most widespread native sedges.
Don’t let the name fool you – while it’s called threesquare, this plant is all about triangular stems that can reach up to nearly 5 feet tall. The stems are sturdy, dark green, and have that distinctive three-sided shape that gives the plant its common name.
Where Does Common Threesquare Grow?
This adaptable native calls home to an impressive 42 states plus several Canadian provinces, including Alabama, Arkansas, Colorado, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Vermont, Virginia, West Virginia, Wisconsin, Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec, Saskatchewan, and Newfoundland. Talk about coast-to-coast coverage!
Should You Plant Common Threesquare?
Here’s the straight scoop: common threesquare isn’t going to be the star of your flower border, but it’s absolutely brilliant in the right setting. This plant is perfect if you have:
- Wet, soggy areas where other plants struggle
- A rain garden or bioswale that needs tough, reliable plants
- Pond edges or stream banks that need erosion control
- A naturalistic landscape where you want authentic native plants
The plant produces small, inconspicuous blue flowers in late spring, followed by brown seeds that persist into fall. While it won’t stop traffic with its blooms, it provides excellent structure and year-round interest in wet areas.
Growing Conditions: What Common Threesquare Needs
This sedge is pretty specific about its needs, but once you get them right, it’s remarkably low-maintenance:
- Moisture: High water needs – think consistently moist to wet soil
- Soil: Amazingly adaptable to coarse, medium, or fine-textured soils
- pH: Tolerates a wide range from 3.7 to 7.5
- Sun: Full sun only – this plant doesn’t do shade
- Climate: Hardy to -38°F, needs at least 120 frost-free days
- Salinity: Medium tolerance, so it can handle some salt
Planting and Care Tips
Getting common threesquare established is pretty straightforward:
- Best planting method: Use sprigs rather than seeds for reliable establishment
- Spacing: Plant 3,450 to 4,800 plants per acre for coverage
- Timing: Spring planting works best
- Establishment: Keep consistently moist during the first growing season
- Maintenance: Virtually none once established – this plant takes care of itself
The plant spreads at a moderate rate through underground rhizomes, so give it room to naturalize. It has a long lifespan and moderate growth rate, reaching its full height of nearly 5 feet by summer.
The Bottom Line
Common threesquare won’t win any Prettiest Plant awards, but it’s an ecological MVP. If you have wet areas in your landscape and want to support native plant communities, this sedge delivers authentic North American character with zero fuss. It’s particularly valuable for erosion control, wetland restoration, and creating habitat in naturalistic settings.
Just remember: this isn’t a plant for dry gardens or shady spots. But put it where it’s happy – in full sun with plenty of moisture – and you’ll have a reliable, long-lived native that connects your landscape to the broader North American ecosystem.
