Calamagrostis arundinacea aka Korean Feather Reed Grass

Calamagrostis arundinacea, or reed grass, is a perennial ornamental grass. It belongs to the grass family, Poaceae. Its native range covers much of Europe and Asia. NC State also lists New Guinea within its range. It is not native to North America. The plant forms dense clumps with upright and arching stems. Rhizomes let each clump spread outward over time.

Garden plants often reach 2–4 feet (0.6–1.2 metres) tall. Their spread is about 2–4 feet (0.6–1.2 metres). Chicago Botanic Garden reports larger plants reaching 5–7 feet (1.5–2.1 metres) in both dimensions. More moisture can lead to larger plants. Sources differ on how fast this grass grows. Green, lance-shaped leaves rise mainly from the plant's base. They have smooth edges and parallel veins. Some leaves exceed 3 feet (0.9 metres) in length. The foliage turns brown, tan, or yellow-beige in fall.

Flower stems rise above the leafy mound in summer. The flower heads form panicles with a pink or reddish tint. Chicago Botanic Garden lists bloom from September to October. The heads fade toward tan as their seeds ripen. Each small, dry fruit is a caryopsis. The fruits are narrow and less than half an inch long. Some sources describe lasting seed heads that add winter interest. NC State notes that plumes may break apart by early winter. Gardeners use both flowers and seed heads in arrangements.

Grow reed grass in full sun or partial shade. Afternoon shade suits sites with hot summers. It prefers soil that stays moist, and tolerates wet ground. Clay, loam, and sandy soils can all support it. The sources also report tolerance of acid soil and salt spray. Florida's guide notes some drought tolerance, despite its moisture preference. NC State and Florida list USDA zones 4–9. Cut old clumps back before new spring shoots emerge. Divide clumps to make new plants.

Use this grass in borders, containers, groups, or single clumps. It suits pond edges, stream banks, and coastal gardens. Dense growth can help screen views and reduce wind. Coastal plantings can also help limit erosion. Sources report few serious pest or disease problems. Deer resistance adds to its value in gardens. Rhizomes may spread fast enough to need control. Chicago warns of aggressive growth in moist, favorable sites. The supplied sources give no species-level evidence for food use or toxicity.