Witch grass (old witch grass)
Panicum capillare

Panicum capillare, known by the common name witchgrass, is a species of grass. It is native plant to most of North America from the East Coast through all of the West Coast and California.
Panicum capillare is an annual bunchgrass growing decumbent or erect to heights exceeding one meter (3 feet). It is green to blue- or purple-tinged in color. In texture it is quite hairy, especially on the leaves and at the nodes. The ligule is a fringe of long hairs.
The inflorescence is a large open panicle which may be over half the total length of the plant, up to half a meter long. At maturity it fans out, spreading to a width over 20 centimeters. As the plant dies and dries, the panicle may break off whole and becomes a tumbleweed.