• Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Barnyard grass is an erect, vigorous, bright-green, summer-active grass that can grow as tall as 120 cm in good conditions
  • Flower stems are stout, prostrate at the base and upright when flowering. Stems are often branched and are hairless between the nodes
  • Leaf blades are flat, soft, usually hairless, 15-50 cm long and 5-15 mm wide. There is no ligule at the base of the leaf blade
  • Seed head is an erect panicle, 10-20 cm long, with 10-20 branches (racemes), each up to 6 cm long. Those at the base are longer than those at the top
  • Racemes are densely packed with spikelets of awned seed (occasionally the awns are very short), green or purple in colour
  • Spikelets are crowded in twos or threes on one side of the axis. Each falls entire at maturity, 3-5 mm long, with two florets, the lower barren the upper bisexual.

Related species

  • Echinochloa crus-pavonis, also known as barnyard grass, is less common and has a drooping and much denser flower head. It is only found on disturbed ground, especially along roadsides and waste areas
  • Echinochloa esculenta (Japanese millet) is a robust annual grass with a compact erect flower head. This is grown here and overseas as a source of birdseed. Plants of this species are often found along roadsides where grain has been spilt. They are also found in stony waste areas, on coastal sands, and in crops
  • Echinochloa telmatophila has long awns in the flower head and is much less common, only found in coastal areas on damp sand flats, on river banks or in roadside gutters in North and South Auckland.


  • Barnyard grass was introduced from Europe and is now a common summer-growing grass throughout the North Island and in Nelson, Marlborough and Canterbury. It is rare in Westland and Otago
  • It is now found in tropical and temperate countries throughout the world.

Life cycle

  • Barnyard grass grows best in high fertility sites and under moderate moisture stress
  • Seeds germinate in late spring and the plants flower in summer. Plants die after seeds are shed
  • Individual plants can become quite large
  • Plants can grow and flower in photoperiods of 8 to 16 hours, but perform better in long day photoperiods
  • It seeds prolifically and can build up large seed reserves in the soil, making it hard to eliminate large populations
  • Some seeds can germinate soon after they mature whilst others may not germinate for several years, especially if buried in the soil.


  • Barnyards grass has occasionally been grown as a grain and in some circumstances it can provide fodder for livestock. However it is not a reliable source of fodder.

Impact on pasture

  • Barnyard grass is rarely a problem in pasture because its seeds cannot germinate in the shade of other plants and it germinates when pasture species are growing quickly.

Impact on crops

  • Barnyard grass competes with summer-active crops, producing a considerable bulk of vegetation in late spring
  • It is a major weed of rice, and is known to reduce yields in maize and other crops.

Cultural control

  • Cultivation or mowing before plants set seed can give useful control in some situations
  • Crop rotation can be a useful tool for limiting the build-up of weeds. Continuous cropping with the same crop builds up weeds that match the growth patterns of the crop. This should be avoided if at all possible by alternating maize, for example, with non-grass crops.

Chemical control

  • Weeds in maize are usually controlled with a mixture of pre-emergence herbicides The most common combination used in New Zealand is a mixture of a triazine, such as atrazine or terbuthylazine for broadleaf control, and a chloroacetamide like alachlor, metolachlor or acetochlor for the control of grass weeds
  • Pre-emergence herbicides must be activated either by mechanical incorporation or by rainfall before it can be taken up by emerging weed seedlings
  • As the crop grows it is important to monitor for weeds that have emerged despite the pre-emergent herbicide, so that post-emergent herbicides like nicosulfuron, mesotrione or topramezone can be applied early enough to be effective.