Muhlenbergia capillaris aka Purple Grass

Muhlenbergia capillaris is a perennial grass in the Poaceae family. Common names include pink muhly grass and hairawn muhly. Its native range spans the central and eastern United States. It extends south through Mexico to Guatemala and the Caribbean. Wild plants grow in open woods, savannas, and rocky sites. In Florida, they also grow in dunes and pine flatwoods.

This grass forms a dense clump with upright, fine stems. Garden plants often reach 3–4 feet (0.9–1.2 m) tall. Their spread is often 2–3 feet (0.6–0.9 m). Florida sources also report heights of 5 feet (1.5 m). Some clumps reach 4 feet (1.2 m) across. RHS gives smaller sizes, to 3.3 feet (1 m) tall. The narrow, green leaves have smooth edges and parallel veins. Sources give leaf lengths from 1–3 feet (0.3–0.9 m). Foliage may stay evergreen or partly evergreen, and turn copper in fall.

Loose panicles of small flowers rise above the leaf clump. Their shades range from pink to purple and reddish tones. Flowering centers on fall, though some sources report a longer season. North Carolina records bloom from September through November. Chicago lists flowers from July through December. The flower heads fade to pale buff as they dry. Small, hard, oval fruits contain grain-like seeds. These fruits are brown and draw little notice on their own. Tan seed heads remain on the plant through winter. Songbirds and small mammals eat the seeds.

Full sun gives the best flower display, though partial shade is possible. Grow it in soil that drains well. It accepts sand, loam, clay, and a broad pH range. Established plants withstand drought, heat, humidity, and poor soil. Florida guidance also reports tolerance of long flooding. Salt tolerance makes it useful near the coast. Sources list USDA zones 7–9 and a broader range of 7–11. RHS rates its UK hardiness as H4. Growth is moderate, and routine care is light.

Use it in borders, native gardens, containers, or large groups. Its late flowers add color after summer plants fade. Cut stems also work in flower arrangements. The clumps give wildlife cover and attract butterflies. Deer tend to avoid this grass. Serious pest and disease problems are uncommon. Muhlygrass mealybug has become a concern in North Carolina. Remove old flower stems in spring. Spring is also the time for seed sowing or division.