Reproducing only by seed.
Stems 5 - 120 cm high, erect, or spreading.
Leaf blades and leaf sheaths densely hairy, the hair 2 - 3 mm long and becoming harsh and prickly as the plant matures; leaf sheath split (B), its margins (a) either separate or overlapping; ligule (b) a dense fringe of hair 1 - 2 mm (1/25 - 1/12 in.) long; no auricles.
Inflorescence (C) a large, loose, open, fluffy panicle with numerous, very fine branches and tiny spikelets (d) at the ends of those branches; the much-branched panicle often wider than long and, on small- to medium-sized plants, often making up Â½ to 2/3 the total height of the plant; mature spikelets 0.7 - 0.8 mm wide by 2.0 - 2.3 mm long florets (â€œseedsâ€) 0.6 - 0.7 mm wide and 1.3 - 1.4 mm long shiny gray-brown with 5 parallel beige veins. At maturity, the stem breaks easily below the inflorescence and the whole panicle is rolled and tumbled by the wind, dropping seed with every bounce. Flowers from July to September.
Fibrous root system.
Witch grass is very common in fields, waste areas, roadsides, backyards, gardens and occasionally in lawns throughout southern Ontario and sporadically in northern and northwestern Ontario.
Corn yield loss (%)*: 1 % at 1 plant/m2 5 % at 5 plant/m2 Soybean yield loss (%)*: 1 % at 1 plant/m2 4 % at 5 plant/m2 *assumes that the weed has emerged with the crop and has been left uncontrolled all season.
It is distinguished from Fall panicum by its densely hairy leaves and leaf sheaths, its very fine, bushy panicle and its smaller seeds; and from Proso millet by its much smaller seeds that are only gray-brown in colour. Seedlings of Witch grass can be distinguished from those of Proso millet only by the size, shape and colour of the mother seed clinging to the primary root.
Witch grass is not known to be toxic.
Witch grass is not a known allergen.
No information exists at this time.
No information available at this time.
Currently none available for this weed. For the latest research on biological weed control: http://res2.agr.ca/Lethbridge/weedbio/index_e.htm#toc
Currently none available for this weed.
Triazine resistant (WSSA group 5) populations exist in Grenville, Grey, Haldimond/Norfolk, Prescott and Wellington counties (ON). For more information on weed resistance: http://www.plant.uoguelph.ca/resistant-weeds/
Witch grass: A. Base of plant B. Leaf-base C. Panicle
Leaf blade: hairy on the upper and lower surfaces.
Leaf sheath: extremely hairy, leaf sheath margins are also hairy.