Witchgrass

Witchgrass is a clumping, summer annual grass with open, branching, flower heads. Other common names for this weed include tumbleweedgrass and witches-hair. It is common throughout California and grows at elevations to about 4900 feet (1500 m). Fall panicum, Panicum dichotomiflorum, a related species, is similar in appearance to witchgrass, but is less common in California. Witchgrass is a desirable member of natural communities (leaves and seeds are an important source of forage for many species of birds and mammals), but it can become weedy in agricultural and landscape sites.
Witchgrass forms “bushy” clumps, grows erect to spreading, and can reach 3 feet (0.9 m) tall. Its stems are round in cross-section, hollow between stem joints, and start branching at the base. Leaves are flat with pointy tips, about 2 to 10 inches (6–25 cm) long, 1/5 to 4/5 of an inch (0.5–2 cm) wide, covered with short to long spreading hairs, and rolled in the bud. In the upper portion of the plant, leaves are gradually more reduced in size. Sheaths are open and about 1-1/2 to 3 inches (4–8 cm) long, often purple- or red-tinged, and covered with short to long, stiff, spreading hairs that have tiny pustule-like bases.
Flowers bloom from June through November. The flower head is erect, has an overall pyramid shape (sometimes egg shape), and is about 6 to 16 inches (15–40 cm) long, and at maturity its branches have an open form and appear diffuse.