Panicum capillare aka Witchgrass

Panicum capillare is an annual grass in the Poaceae family. Its common names include witchgrass and old witch grass. Its native range spans Canada, northern Mexico, and the Caribbean. It grows in temperate climates and is not native to Britain or Ireland. Wild plants grow on open sandy or stony ground. They also occur on land used for crops.

Plants form loose tufts of flat, narrow, mid-green leaves. Each leaf can reach about 1 foot (0.3 m) long. Garden plants stand about 2–3.3 feet (0.6–1 m) tall. Their spread reaches about 1.6 feet (0.5 m). The plant reaches its full size within one growing year. It sheds its foliage rather than keeping green leaves year-round. Its modest size suits beds, borders, and pots.

Flowers appear in late summer and autumn. Tiny greenish-brown spikelets form dense panicles on fine branches. These branched flower heads give the grass a light look. Once seeds ripen, the seed-bearing stem can break free. Wind then carries it away and spreads the seed. The small seeds have a mild taste. People can cook them whole or grind them into flour. They can also mix them with corn. Their tiny size makes collecting and using them awkward.

Grow this grass in full sun and soil that drains well. Moderately fertile soil suits it, including chalk, loam, and sand. It accepts acid, neutral, or alkaline soil. The listed moisture range runs from dry to moist. Both open and sheltered sites suit it. RHS assigns it UK hardiness H5; PFAF lists USDA zones 4–8. Sow seed in early spring to start new plants. Remove dead leaves and spent flower stems when growth ends.

Suggested uses include prairie-style beds, meadows, and wildlife gardens. It also suits coastal, courtyard, and informal gardens. Growers can use the stems for cut flowers. The grass also provides material for brooms. RHS reports few usual pest or disease problems. Weed spread is a separate concern in cultivated ground. PFAF records it as an occasional heavy weed of East Anglian carrot crops. PFAF lists no known hazards, but this does not establish safety for every use. It records past medicinal uses, including leaf infusions to cause vomiting. Such records do not show that these treatments are safe or effective.