Sporobolus michauxianus aka Prairie Cordgrass

Sporobolus michauxianus is a grass that lives for years. It belongs to the grass family, Poaceae. Sources use the name Spartina pectinata for this grass. Common names include prairie cord grass and slough grass. It grows across much of North America. Its range runs south from the subarctic. It reaches Oregon, New Mexico, Louisiana, and North Carolina. Wild plants grow in fresh water marshes and wet, open valleys. They also grow beside ponds, roads, and railways. The grass grows in both wet and dry prairies.

This warm-season grass grows most during the summer months. It forms dense clumps of leaves that curve in arches. Plants in flower reach about 4–7 feet (1.2–2.1 metres) tall. Reports give garden spreads of up to 7 feet (2.1 metres). Rhizomes, or stems below ground, spread past the clump. They form broad groups of plants. The strong stems stand upright or bend in an arch. They feel smooth and have a pale green hue. A cut across a stem shows its round shape. The plant has a coarse look, not fine leaves.

The glossy, dark green leaves turn yellow in autumn. The narrow blades reach 4 feet (1.2 metres) long. Each curves up, then bends down toward its tip. Most leaves grow along the lower half of each stem. Each has a clear midrib and fine veins along its length. The sharp edges can cut skin, so wear gloves when handling. White hairs form a ring where each blade joins its sheath. Flower stems rise above the leaves in July and August. The flowers range from pale yellow to the color of straw. They form open heads with branches. Spikes line the branches like the teeth of a comb. Brown fruits that look like grains follow the flowers. The seedheads remain in fall.

Full sun suits this grass, but it accepts some shade. It grows best in rich loam kept moist or wet. It also accepts clay, sand, and rocky ground. Drier soil slows growth and curbs its spread. Plants cope with spells of hot, dry weather and salt. Sources place it in USDA zones 4–9. You can divide plants to raise new ones. Seed that can sprout may be hard to get.

Garden uses include pond edges and water gardens. It also suits plantings left to spread on their own. Its spreading roots help hold soil on slopes and streambanks. Ducks sometimes eat the seedheads. Muskrats eat the roots and leaves. Wetland birds use the grass for shelter and nests. People once used it to thatch lodges. Its strong spread can make it invasive in plantings. Moth larvae feed on it, but serious pest problems are rare. The evidence does not show whether people can eat it. Nor does it show whether the plant is toxic.