Panicum virgatum (Switchgrass)
|Also known as:
|part shade, sun; prairie, savanna, open woods, dunes, roadsides, railroads
|3 to 6 feet
|Wetland Indicator Status:
|GP: FAC MW: FAC NCNE: FAC
|MN county distribution (click map to enlarge):
|National distribution (click map to enlarge):
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Airy pyramidal cluster at the top of the stem, with many slender, spreading to ascending branches, most with a few side branches. The cluster is 8 to 16 inches long and 1/3 to half as wide. Branches are mostly whorled or nearly so.
Along branches and side branches are one or more hairless, awnless spikelets (flower clusters), each 2.2 to 5.6 mm long, up to 1.5 mm wide, and with a single fertile flower. The glumes (bracts at the base of the spikelet) are unequal in length, the first half to 2/3 as long as the spikelet, the second as long as the spikelet and conspicuously veined. The lemma (2 bracts surrounding the flower) are as long as or slightly shorter than the spikelet, the sterile lemma conspicuously veined, the fertile lemma slightly shorter and without veins. The glumes and lemma are all narrowly egg-shaped, tapering to a sharply pointed tip, and spread apart as the flower develops, with the stamens and styles visible at the opening. Spikelets are green to purple, on wiry stalks.
Leaves and stems:
Leaves are all alternate, ascending to floppy, 7 to 20 inches long and ¼ to ½ inch wide, flat, and hairless except near the base, which is often variously covered in long, silky hairs. Leaf edges are rough.
The sheath is open with a distinct “V” at the front. The ligule (membrane where the leaf joins the sheath) is white with a dense tuft of silky hairs up to 4 mm long. Nodes are hairless and usually dark purplish brown. The culm (stem) is erect, stout and hairless. Plants often create dense tufts from scaly rhizomes.
Switchgrass is quite a robust species and tolerates a wide variety of growing conditions, which makes it popular in various native plant restoration projects. It is also an important forage and biomass crop, and there are a surprising number of cultivars in the nursery trade. A grass for everyone, it would appear. It is usually recognized without too much trouble: look for a big clump of tall, leafy grass with a large open cluster of hairless, awnless spikelets on wiry stalks.
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Photos by K. Chayka taken in Anoka and Ramsey counties. Other photos courtesy Peter M. Dziuk.
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