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Ministry of Agriculture, Food and Rural Affairs

Fall Panicum

Scientific Name: Panicum dichotomiflorum (L.) Michx. var. geniculatum (Wood.) Fern.

Other Names: PANDI, panic d’automne géniculé, Smooth panicum, Smooth witch grass, Spreading panic grass, Wire grass

Family: Grass Family (Gramineae)

General Description: Annual, reproducing only by seed

Habitat: Fall panicum is a native plant in eastern North America. It infests many thousands of acres of prime corn land in the 6 south-western counties of Ontario and is present in many more farms in all the counties south and west of a line from Hamilton to Grand Bend. Outside this region it is known to occur only occasionally in cultivated land in central Ontario, in streamside locations along Bear Creek southeast of Ottawa, and in several waste areas in Ottawa city and along the St. Lawrence River.

Seedlings

  • Sheaths and undersides of the first leaves are hairy
  • Blades and sheaths higher up the stem usually hairless
  • Ligule a fringe of hair 1.5- 3 mm(1/16- 1/8 in.) long
  • No auricles
  • New leaves appear rolled up upon emergence

Stems

  • 1 to many from a coarse fibrous root system
  • 10- 180 cm (4 in.- 6 ft.) long
  • Erect or spreading or lying nearly prostrate on the ground
  • Bending in a zigzag manner at each node or joint
  • Terminal panicle at the end of each stem

Leaves

  • Sheath somewhat inflated or loosely fitting around the stem just above each node
  • Sheaths split, their margins are very thin, membranous, white or colourless and separate or overlapping

Flowers

  • Spikelets borne singly at the ends of the tiny branches
    2.5- 2.7 mm (1/10 in.) long by 1.0- 1.1 mm (1/25 in.) wide
  • Each contain a seed:
    • 1.8- 2.0 mm (1/14- 1/12 in.) long by 0.9- 1.0 mm (1/25 in.) wide
    • Grey-brown
    • 5 parallel beige veins
  • Flowers from August to September

Often Confused With
Witch Grass (Fall panicum is distinguished from witch grass by its coarser panicle, the zigzag appearance of its longer stems, and the absence of hair on the leaf sheaths and leaf blades in the upper part of the plant)
Proso Millet (Fall panicum is distinguished from Proso millet by its hairless upper leaf sheaths and blades and its smaller spikelets and seeds that are only grey-brown in colour)

Fall panicum Fall panicum panicule Fall panicum A. Plant B. Leaf-base C. Panicule D. Spikelets
Click to enlarge.