Avenella flexuosa aka Wavy Hairgrass

Avenella flexuosa is a perennial grass: it lives for years. It belongs to the Poaceae family. Garden sources use the name Deschampsia flexuosa too. People call it wavy hair grass or crinkled hair grass. Its wide native range spans Europe, Japan, and the Malesian mountains. It includes Macaronesia, parts of Africa, Greenland, and North America. It reaches southern South America and the Falkland Islands too. It is native to Britain and Ireland. In the wild, it grows in open woods and grasslands. It also grows in fields and on slopes.

This cool-season grass forms a dense tuft of fine leaves. In flower, garden plants reach about 2–3 feet [0.6–0.91 metres]. RHS gives a top height of 3.3 feet [1 metre]. Plants can spread to 2 feet [0.61 metres]. RHS lists smaller widths, though. The low leaf mound reaches about 1.3 feet [0.4 metres]. Narrow leaves arch out, and their edges may roll inward. They range from blue-green to dark green. RHS calls the leaves evergreen. Missouri Botanical Garden says plants keep some leaves through winter.

Thin, wavy stems hold loose panicles high above the leaves. These flower heads branch out. Their small spikelets have purple, brown, bronze, or silvery tones. RHS gives early and midsummer as the bloom time. Missouri Botanical Garden gives July to September. The open flower heads catch light. They give groups of plants a softer look. They turn gold as the seeds ripen. Old stems can add interest once the flowers fade.

Grow this grass in sun or part shade. It suits shade where many grasses grown for looks struggle. Deep shade means fewer flowers, though. It prefers moist soil that drains well, with added organic matter. It copes with dry shade and drought too. Clay, loam, and sand suit it, with acid or neutral pH. RHS rates its hardiness H6. Missouri Botanical Garden lists USDA zones 4–7. High heat and damp air can cause poor growth south of zone 7.

Use it in woodland gardens, borders, or groups left to naturalise. It also suits large rock gardens and pond or stream edges. Ferns and hostas suit shaded beds with this grass. Reports note no serious pest or disease problems. Plants may grow from their own seeds where sites suit them. Cut back old leaves in late winter, before new shoots emerge. Remove old flower stems in autumn or before spring growth. Grow new plants from seed, or split clumps once established.