Scirpus cyperinus aka Cotton Grass Bulrush

Scirpus cyperinus is a perennial sedge known as woolgrass. It looks like grass but belongs to the sedge family. Its native range covers south-central and eastern Canada, the United States, and eastern Mexico. It grows in marshes, swamps, and wet meadows. It also grows beside streams, ponds, and wet ditches. Disturbed wet ground can support it too.

Plants form dense clumps with green leaves that arch outward. Garden plants reach about 3–5 feet [0.91–1.52 metres] tall. North Carolina State lists heights up to 6 feet [1.83 metres]. Clumps spread about 2–4 feet [0.61–1.22 metres] wide. Creeping rhizomes let them expand into larger colonies over time. Upright flowering stems rise above the basal leaves. These unbranched stems range from three-angled to rounded in section. Each stem bears five to ten long, narrow leaf blades. The leaves turn yellow-brown as the growing season ends.

Small flowers grow in branched clusters at the stem tips. The clusters measure about 4–6 inches [0.10–0.15 metres] across. Green flower heads turn brown as they age. Sources give bloom dates from late June through October. Missouri Botanical Garden lists late June and July. North Carolina State lists July through September. Chicago Botanic Garden lists September and October. Brown fruits show from August through October. The reddish-brown heads add interest in fall and winter. Birds and small mammals visit the plants.

Grow woolgrass in moist or wet soil, including shallow water. It prefers full sun but also grows in partial shade. Some shade helps in places with hot summers. Sources place it in USDA hardiness zones 4–8. It suits rain gardens, bog gardens, and damp low spots. Plant it along pond edges or in large water gardens. Submerged containers offer another way to grow it. It also works in borders and mass plantings. Divide clumps in spring, or start plants in spring or fall. It can spread through rhizomes and seed. Sources report low upkeep and no serious pest or disease issues.

Plants For A Future lists cooked seeds as edible. They can serve as a rice substitute. That source reports no known hazards or medicinal uses. People have woven the stems into mats, ropes, and bags. The fruiting heads have also supplied stuffing for pillows.