Switch grass is a warm season grass with deep, fibrous roots, making it an outstanding plant for erosion control and soil stabilization. Photo credit: Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database / USDA SCS. 1991. Southern wetland flora: Field office guide to plant species. South National Technical Center, Fort Worth.
FIRST IMPRESSIONS: Panicum virgatum is an elegant vase shaped grass with an abundance of seasonal interest. In spring, a fresh crop of glaucous stems and graceful bluish-green arching leaves rise from the earth. Mature plants are statuesque and crowned with airy panicles of summer spikelets. In late evening, the tiny purple tinged spikelets seem to dance above the foliage. In autumn and winter, leaves and seeds develop an amber glow. This handsome grass thrives in prairie type settings or in sunny gardens with moist, average or dry soils.
HABITAT & HARDINESS: Panicum virgataum ranges through most of the southern Canadian provinces and the contiguous United States except for Washington, Oregon and California. The species is most common in the Midwestern Plains of North America.
Plants are indigenous to prairies, savannas, glades, rocky bluffs, stream banks, open woods, sand dunes, borders of marshes, roadsides, ditches and fields. This species is more tolerant of disturbance than most other prairie grasses.
Panicum virgataum is hardy from USDA Zones 3-9.
PLANT DESCRIPTION: Panicum virgataum is a robust bunch grass that produces many vertical culms from short rhizomes.
The linear leaves are arranged alternately on the blue-green glaucous stems. The arching blades are gray green, medium green or bluish green with yellow or red fall tints. They are ½” wide and 24” long with bases that wrap around the stems.
In late summer as the foliage reaches mature height, open airy flower panicles appear. The panicles are pyramidical in outline. They consist of many small spikelets held on wirey stems. The ripe seed that follow are soft tan. Dried seed and foliage develop a coppery winter hue.
Plants are anchored by an extensive fibrous root system that can penetrate the soil to a depth of 10’ while top growth attains a 3-6’ height and 3’ spread.
CULTURAL & MAINTENANCE NEEDS: Panicum virgatum prospers in sunny sites with average to moist soil. Plants tolerate clay, alkalinity, drought, moderate salinity and seasonal flooding.
The only maintenance needed is to cut or burn this grass to the ground in late winter.
Avoid excess shade, fertilizers or abundant water that promote weak sprawling stems.
This species can expand into colonies by seeding and expanding from rhizomes. In small gardens with ideal growing conditions, deadheading may be needed to prevent excessive seeding.
LANDSCAPE USES: This grass is an appealing Accent or Mass Planting for Wildlife Gardens, Prairies or Meadows. Panicum virgatum provides Erosion Control, Fall Color, Winter Interest, Interesting Blooms and Showy Seedheads. Plants are appropriate for Cottage Gardens, Low Maintenance Plantings, Water Wise Landscapes, Rain Gardens, Roadsides, Restoration Projects, Stormwater Management and Perennial Borders.
COMPANION & UNDERSTUDY PLANTS: Try pairing with Aster umbellatus, Coreopsis tripteris, Echinacea purpurea, Hibiscus moscheutos, Liatris spicata, Rudbeckia hirta or Schizachyrium scoparium.
Sorghastrum nutans has similar height, foliage and cultural needs and can be substituted if needed.
TRIVIA: Panicum virgatum is a dominant species of the Midwestern Tallgrass Prairies. This grass along with Andropogon gerardii, Schizachyrium scoparium and Sorghastrum nutans are sometimes called "The Four Horsemen of the Prairie".
Plants host the caterpillars of several skipper species. The seed are eaten by a variety of birds and small rodents. Tender young foliage is browsed by deer and livestock and dense upright growth provides winter cover for wildlife.
For more information on this plant, visit the USDA PLANTS Database: http://plants.usda.gov/java/profile?symbol=pavi2