Square-stem spikerush is a native spikesedge found in central and eastern North America with additional populations in the Pacific states and central Mexico. It is found growing along freshwater bodies of water, such as lakes, ponds, streams and along river and lake shores. This rhizomatous sedge has a sharply 4-angled spongy stem and grows 2-3 feet tall. The blooms are on a single spikelet with several small flowers covered in brown bracts that occur during the summer. The leaves are sheaths near the base of the stem. The plant is not aggressive and spreads slowly by rhizomes. This plant can be used in shallow freshwater sites in full sun. It tolerates wet soils to standing water up to 12 inches. This plant provides shelter to aquatic animals and food to various birds. It may be difficult to find for sale. Quick ID hints Slow rhizomatous spreader Culms acutely quadrangular Flowers-perianth bristles Insects, Diseases, and Other Plant Problems: No significant problems
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Herbaceous Perennial; Native Plant; Ornamental Grasses and Sedges; Water Plant
Life cycle
Perennial
USDA zones
5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Loam (Silt)
Soil pH
Acid (<6.0); Neutral (6.0-8.0)
Soil drainage
Frequent Standing Water | Occasionally Wet
Available space
Less than 12 inches
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 2 ft. 0 in. - 3 ft. 0 in. | Width: 1 ft. 0 in. - 2 ft. 0 in.
Growth rate
Slow
Maintenance
Medium
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Erect
Texture
Medium
Leaf color
Green
Leaf type
Sheath; Simple
Leaf arrangement
Alternate
Leaf shape
Linear
Leaf margin
Entire
Leaf size
< 1 inch wide
Hairs present
No
Leaf detail
Leaves are bladeless sheaths near the base of the stems. Above the waterline, they are green, while below the waterline they are white.
Flower color
Brown/Copper; Orange
Flower form
Insignificant
Flower size
< 1 inch
Flower detail
Spikelets of tiny flowers covered in brown bracts occurring during the summer.
Bloom time
Fall; Summer
Fruit color
Brown/Copper; Gold/Yellow
Fruit type
Achene
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
The fruit is a seed, surrounded by scales. Yellow-brown oval achene that is wider in the middle, and tapered at each end. Stripes/ridges run from end to end.
Stem color
Green
Stem detail
Spongy, square green stem
Wildlife & Ecology
Native status
Native
Origin
USA, Canada, Mexico
Distribution
AL , AR , CA , CT , DC , DE , FL , GA , IL , IN , KS , KY , LA , MA , MD , MI , MO , MS , NC , NJ , NY , OH , OK , OR , PA , SC , TN , TX , VA , WI , WV
Wildlife value
Provides food for ducks and geese and shelter for amphibians, fish and other aquatic wildlife