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Weed Identification

fall panicgrass



Scientific Name

Panicum dicotomiflorum

Other Common Names:

western witchgrass


Seeds germinate in late spring or early summer and plants quickly grow to heights between 20 in to 40 in. Plants are erect to sprawling and often root at the nodes of bent stems.


Seedling leaves are hairy on the bottom but not on the top. Hairs are common on young seedlings but become less common on upper leaves of older plants. Plants lack auricles and stems are smooth. The ligule is split with the top fringe being hairs and the lower portion a solid membrane. Overall the hairy ligule is shorter than that of the foxtails (1 to 2 mm long).

Identifying Characteristics

Stems grow in a zigzag fashion, turning at each swollen node. Stems are shiny and hollow when cut open. Older plants resemble Johnsongrass in that leaves are wide and large but Johnsongrass stems are solid and the plants are erect, not sprawling. Young seedlings have thin cotyledons, hairy ligules, and hairs only on the bottom of lower leaves.

Flower Seed Head

The seedhead is an open panicle that is up to 16 in long and may appear green or purplish at maturity. Each spikelet produces a single light brown seed.

Seed Fruit

Seeds are awnless, light brown and about 1.5 to 2 mm long.

Where Found

Typically a weed of cultivated areas such as home gardens, row-crop agriculture, and nursery beds. Seed will germinate in open or disrupted areas of turfgrass and are not uncommon in turf in mid to late summer. Although plants may occur in turfgrass, they are much less common than other summer annual grassy weeds such as crabgrass and goosegrass.

Leaf Hair on Upper Surface

no hairs
hairs from base to tip

Leaf Arrangement

rolled in bud

Mature Leaf Width

6 to 15 mm
more than 15 mm





Root Structure


Life Cycle

summer annual


not present



Ligule Length

1-2 mm
2-3 mm

Plant Type