Photo Credit
Photo courtesy of Sally and Andy Wasowski, Lady Bird Johnson Wildflower Center, www.wildflower.org.

Switchgrass

Scientific name
Panicum virgatum
Also Known As
Blackbent, Tall panic grass, Tall prairie grass, Thatchgrass, Wild redtop
Plant Family
Plant Group
Switchgrass has long been popular as a forage grass and for erosion control, but has more recently been touted for its ornamental use and for development as a possible biofuel crop. Several cultivars are available for garden use.
Identification Hints

Switchgrass is a large grass growing with bluestem and indian grass species in tallgrass prairies. It is distinctive in having flowers in large open panicles (loose and many-branched). The leaves are generally 30-90 cm long. When the seeds ripen in the fall, they often turn a pink to purple to golden color. Indiangrass (sorghastrum) also has big panicles but its panicles are silky hairy and its spikelets are golden brown.

Did You Know?

Switchgrass is a key species of the tall grass prairie. It is used for forage and ornamental use. Switchgrass has several cultivars. As a crop, switchgrass is self seeding, which means that farmers do not have to plant and re-seed after annual harvesting. Once established, switchgrass can survive for ten years or longer. Switchgrass made news headlines recently because some searchers believe it has great potential for producing biofuel (substitute for diesel oil). It is a good candidate for use as a biofuel because of its prodigious growth and tolerance of a wide variety of conditions.

Leaves
The coarse leaves are 12 to 35 in (30 to 90 cm) long, 0.2 to 0.5 in (0.5 to 1.3 cm) wide, and have a prominent midrib. They are flat and glossy. The stem is erect, coarse, and sometimes has a reddish tint.
Flowers
The flowers have well developed panicles (branched, indeterminate clusters). Spikelets are attached with a stalk to open branches that are attached to the main flower stem. The main flower stems vary in size from 4 to 22 in (10 to 56 cm) long and about 1.5 to 8 in (4 to 20 cm) wide. The tiny spikelets are egg-shaped, solitary, and found at the ends of the long branches. The spikelets are 0.1 to 0.2 in (0.25 to 0.5 cm) long.
Fruits
When ripe, the seeds sometimes take on a pink or dull purple tinge. They turn golden brown when the foliage turns color in the fall.
Habitat
Switchgrass is a versatile and adaptable plant. It can grow in many types of weather conditions and soil types. It grows particularly well in the areas of tallgrass prairies. Switchgrass also grows on dry slopes, sand, open woodlands, shores, riverbanks, and marshes. It grows best when there is adequate moisture and deep rich soil.
Bloom Time
The leaves begin to develop as early as March. Flowering begins in June in much of its range but can occur through November. Switchgrass seeds are found in late August to early September, but can be dispersed in late fall and early winter depending on latitude and elevation. As a warm season perennial grass, most of its growth occurs from late spring through early fall. It becomes dormant and unproductive during the colder months. The productive season in its northern habitat can be as short as three months, but in the southern reaches of its habitat, the growing season may be as long as eight months (around the Gulf Coast area).
States
AL, AR, AZ, CO, CT, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, PA, RI, SC, SD, TN, TX, UT, VA, VT, WI, WV, WY