Blackwell switch grass

Panicum virgatum is a robust, warm-season perennial bunchgrass of the Poaceae family, growing 0.5 to 2.5 metres tall from short, scaly rhizomes that form loose to dense tussocks. The smooth, erect, hollow culms are unbranched, with conspicuous swollen nodes and often glaucous internodes. The long, flat to slightly involute leaf blades are 10 to 60 centimetres long and 3 to 15 millimetres wide, blue-green or sometimes purplish, with a prominent white midrib, scabrid margins and a distinctive tuft of long white hairs at the throat where the blade meets the smooth or sparsely hairy sheath; the ligule is a fringe of short hairs. The inflorescence is a large, diffuse, open, finely branched terminal panicle 15 to 50 centimetres long and almost as wide, with delicate spreading branches bearing solitary, ovoid spikelets 3 to 5 millimetres long, each containing one fertile floret subtended by two unequal pointed glumes; the spikelets often acquire a purple cast at maturity. Native to tallgrass prairies, savannas and open ground across most of North America east of the Rocky Mountains.