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Native Plant Trust: Go Botany Discover thousands of New England plants

Panicum virgatum — switch panicgrass

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Facts

Switch panicgrass is a North American native perennial drought-tolerant grass that is a palatable forage grass and is planted domestically and worldwide for range and wildlife habitat improvement. It is one of the main species being considered as a biofuel crop, but calculations of carbon emissions savings need to include the effects of widespread land-use conversion if this species begins to be widely grown for biofuels.

Habitat

Anthropogenic (man-made or disturbed habitats), brackish or salt marshes and flats, marshes, meadows and fields, shores of rivers or lakes, wetland margins (edges of wetlands)

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf blade width
2–15 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
2.5–8 mm
Glume relative length
one or both glumes are as long or longer than all of the florets
Awn on glume
the glume has no awn
One or more florets
  • there is more than one floret per spikelet
  • there is one floret per spikelet
Lemma awn length
0 mm
Leaf ligule length
2–6 mm
Show all characteristics
  • Flowers

    Anther number
    3
    Awn on glume
    the glume has no awn
    Bristles below spikelets
    no
    Floret lower bract texture
    the lemma is hard and firm
    Floret number
    2
    Floret types within spikelet
    there are at least two distinct forms of florets within one spikelet
    Glume awn length
    0 mm
    Glume keel
    the glume keels are smooth and hairless
    Glume relative length
    one or both glumes are as long or longer than all of the florets
    Glume shape
    the glume is flat or curved in cross-section
    Glume veins
    • 5
    • 7 or more
    Glumes per spikelet
    2
    Inflorescence arrangement
    the spikelets are uniform
    Inflorescence axis orientation
    the inflorescence axis is straight
    Inflorescence branch roughness
    the inflorescence branches are somewhat to very rough
    Inflorescence branches
    the flowers are attached to branches rather than to the main axis of the inflorescence
    Inflorescence crowding
    the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    100–550 mm
    Inflorescence length to width ratio
    2.5–2.8
    Inflorescence type (general)
    the spikelets are borne on stalks or on branches
    Inflorescence type (specific)
    the inflorescence is branched, and the branches do NOT both grow from the same side of the plant AND look like spikes
    Inflorescence width
    40–200 mm
    Inforescence position
    the spikelets are mainly carried at the end of the stem
    Lemma awn base
    NA
    Lemma awn coiled
    NA
    Lemma awn length
    0 mm
    Lemma awn number
    the lemma has no awn
    Lemma awn orientation
    NA
    Lemma base hair length
    0 mm
    Lemma base hairs
    NA
    Lemma base length
    0 mm
    Lemma cross-section
    the lemma is flat or rounded if you cut across the midpoint
    Lemma hairs
    the lemma is hairless between the veins
    Lemma keel hairs
    the keel of the lemma is hairless
    Lemma marginal vein hairs
    the marginal vein of the lemma is hairless
    Lemma surface
    the surface of the lemma is relatively smooth (not counting any longitudinal veins or hairs)
    Lemma tip
    the lemma tip is a simple point, with or without an awn (long narrow extension ending in a point)
    Lemma vein number
    • 3
    • 5
    • 7 or more
    Lower glume length
    1.8–3.2 mm
    Lower glume relative length
    the lower glume is one third to three quarters as long as the upper glume
    One or more florets
    • there is more than one floret per spikelet
    • there is one floret per spikelet
    Palea length
    3–3.5 mm
    Palea relative length
    palea is one half to fully as long as lemma
    Reproductive system
    some flowers on the plant have both carpels and stamens, while other flowers have only one type of reproductive organ (polygamous)
    Spikelet axis tip
    there is no extension of the spikelet axis beyond the tip of the spikelet
    Spikelet disintegration
    the spikelet breaks off below the glumes
    Spikelet length
    2.5–8 mm
    Spikelet number per node
    0
    Spikelet pedicel
    the spikelets have pedicels
    Spikelet pedicel length
    0.5–20 mm
    Spikelet shape
    • the spikelets are lanceolate (lance-shaped, widest below the middle and tapering narrowly to the ends) in profile
    • the spikelets are ovate (egg-shaped, widest below the middle with rounded ends) in profile
    Spikelet width
    1.2–2.5 mm
    Spikelets spiny
    the spikelets do not appear spiny
    Tip of glume
    the tip of the glume is not divided (though it may have an awn on it)
    Upper glume length
    2.8–8 mm
    Upper glume relative length
    the upper glume is more than one half as long as the lowest lemma
    Upper glume shape
    the upper glume is widest at or below the middle
  • Fruits or seeds

    Seed length
    2–3 mm
  • Growth form

    Horizontal rooting stem
    no
    Lifespan
    the plant lives more than two years
    Rhizomes
    yes
    Roots
    the plant has rhizomes (horizontal underground stem with roots growing from it)
  • Leaves

    Basal leaves
    the plant has few or no leaves coming from the base of the flowering stem
    Leaf auricles
    the leaves do not have auricles
    Leaf blade base
    the leaf is tapered gradually to the base
    Leaf blade cross-section
    the leaf blade is more or less flat in cross-section, or slightly folded or rolled inwards
    Leaf blade hairs
    • the leaf blade is hairless, but it may have tiny prickles that give it a sand-papery feel
    • the leaf blade is hairy
    Leaf blade length
    10–60 cm
    Leaf blade texture
    the leaf blade is rough and sandpapery
    Leaf blade width
    2–15 mm
    Leaf ligule length
    2–6 mm
    Leaf ligule type
    the leaf ligule is in the form of a membrane with fine hairs
    Leaf margin glands
    there are no glands along the edges of the leaf blade
    Leaf sheath closed around stem
    the margins of the leaf sheath are overlapping and not fused together except in the basal half (or less)
    Leaf sheath hairs
    • there are hairs on the surface of the leaf sheath
    • there are no hairs on the surface of the leaf sheath
  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • brackish or salt marshes and flats
    • edges of wetlands
    • man-made or disturbed habitats
    • marshes
    • meadows or fields
    • shores of rivers or lakes
  • Stem, shoot, branch

    Hairs at nodes
    the stem nodes are hairless or they have very sparse hairs
    Plant height
    40–300 cm
    Stem hairs
    the stem is nearly to completely hairless
    Stem orientation
    • the stems are upright
    • the stems trail at the base, but turn upwards at the tips
    Stem spacing
    • the stems grow close together in compact clusters or tufts
    • the stems grow singly or a few together (they may form diffuse colonies)
    Stem thickness at base
    3–5 mm

Wetland status

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

In New England

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
present
Vermont
present

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
widespread (S-rank: S5)
Vermont
uncommon (S-rank: S3)

var. spissum

Maine
unranked (S-rank: SNR)

From Flora Novae Angliae dichotomous key

9.  Panicum virgatum L. N│E

switch panicgrass. Panicum virgatum L. var. cubense Griseb.; P. virgatum L. var. spissum Linder • CT, MA, ME, NH, RI, VT. Fields, roadsides, pond shores, railroads, upper edge of saline to brackish marshes.

Native to North America?

Yes

Sometimes confused with

Panicum amarum:
panicle contracted, with strictly ascending to appressed branches, and plants glabrous throughout (vs. P. virgatum, with panicle open, with ascending to spreading branches, plants sometimes pubescent on the leaf sheaths and/or blades).

Synonyms

  • Panicum virgatum var. cubense Griseb.
  • Panicum virgatum var. spissum Linder

Family

Poaceae

Genus

Panicum