Pennisetum glaucum, Setaria glauca

Scientific Name Pennisetum glaucum (L.) R. Br., Setaria glauca (L.) P. Beauv.
Synonyms Setaria glauca (L.) P. Beauv., Chaetochloa glauca (L.) Scribn., Panicum glaucum L., Panicum pumilum Poir., Pennisetum glaucum (L.) R. Br., Setaria erythraeae Mattei, Setaria lutescens (Weigel) F. T. Hubb., Setaria pumila (Poir.) Roem. & Schult., Setaria rubiginosa (Steud.) Miq.
Common Names English: Yellow foxtail, yellow bristle-grass; German: Gelbe Borstenhirse; French: Sétaire glauque; Spanish: almorejo (glauca)
Description Tufted annual grass, very variable in size and vigor, ranging from a few centimeters up to more than 100 cm ( 39.37 inch) high.


Characteristic Features

Yellow foxtail spikes are typically yellowish, spikes of other foxtail species become brown.

Young Plant

S. glauca is much branched and there may be rooting at lower nodes. The stem base and lower leaves are often red or purplish, especially under infertile soil conditions. The youngest leaf is rolled. 1.30 m (51.18 inch) tall.


Stem is flattened and up to 1.30 m (51.18 inch) tall, sometimes more or less branched.


Leaves up to 30 cm (11.81 inch) long by (4 -)10 mm (0.157 - 0.39 inch) wide, and glabrous except for a few long hairs on the upper surface near the base. Ligule is a fringe of hairs, sometimes on a short membrane, up to 3 mm (0.118 inch) long.
No auricles.
Sheaths are keeled.

Propagation Organs


Erect spike-like panicle, very variable in length, from few cm up to 15 cm (5.9 inch) long, about 1 cm (0.39 inch) in diameter. Axis densely pubescent. Spikelets 1.5 to 3.5 mm (0.059 - 0.137 inch) long, awnless, each subtended by 4 -12 scabrous bristles, 3 - 8 mm (0.118 - 0.315 inch) long, yellow, orange, tawny or purplish in color.
Spikelets are ovate, with lower glume about two thirds as long as the lemmas and the upper glume about half as long, exposing the transversely wrinkled upper lemma.

Flowering Period



Caryopsis in late summer or early autumn.


Germination in early summer.

Viability of Seeds

Up to 15 years.


By seed. Seeds usually are dormant at maturity and require an afterripening period of 2 - 4 months before they can germinate.
400 - 800 seeds per plants.



P. glaucum is a temperate species, especially in Europe and North America.


It prefers fertile soils, rich in nitrogen.

Additional Crop Information

Also in soybean, barley, potato, beetroot, plantain, sugarcane, coffee (arabica), pineapple, tobacco

Agricultural Importance

P. glaucum is a serious weed in most crops of both temperate and tropical zones, annual and perennial, including vegetables, tree crops and grassland, plant of disturbed ground, roadsides and waste places, reaching elevations up to 300 m (984 ft). It often emerges late in corn and has become less sensitive to many herbicides.


Useful non-chemical contribution to Integrated Weed Management

Manual removal or cultivation as needed before seeds mature can help control infestations.

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