Panicum virgatum, or Switch Grass, is a perennial, rhizomatous grass native from the plains of Southern Canada to the American tall grass prairies to Mexico and Central America. It forms dense clumps 3-6 ft. (0.9-1.9 m) tall. Leaf sheaths are glabrous; blades are up to 1/3 inches (1.6 cm) wide, flat, glabrous or sometimes pilose. We grow them for research. Our scientist is studying them as a source for biofuel and for plant-microbe interactions. They are of very easy culture whether in container or in the landscape. Plants are hardy in USDA zones 4-9.
Blooming: The inconspicuous flowers of this plant bear purplish red anthers on 20 inch (50 cm) loose panicles. The seed is teardrop-shaped to 1/8 inches (0.30 cm) long.
Culture: Panicum virgatum need full sun to very light shade with a moist to wet soil. In containers, we use a soil mix consisting of equal parts of loam and sand. Plants are kept moist at all times for optimal growth. We do not fertilize the plants at all. Fertilizer will kill many of the microbes that are being studied. Plants grown in rich soils or very dry soils do not do very well, although they will tolerate dry soils. During the winter months, older plants are allowed to go dormant and placed in the cool rooms where nighttime temperatures fall to 48°F (9°C). New plants are started from seed and grown under supplemental lighting for good growth.
Propagation: Panicum virgatum is propagated by division of older clumps and from seed. The seed needs to be exposed to light to germinate; we surface sow the seed and cover them with white paper. Most seed will germinate in 14-21 days at 70°F (22°C).
Panicum virgatum was featured as Plant of the Week June 13-19, 2008.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.