Common sandbur (Cenchrus echinatus)

Introduction:

Cenchrus echinatus is an annual grass that is a native of tropical America, but has now widely colonised tropical and temperate zones worldwide. Though it is typically associated with dry, sandy habitats it can also grow in moist areas, where it may be long-lived and reach a much larger size. It is recognisable by the burrs it produces, which readily attach themselves to animals and clothing, making C. echinatus easily dispersed. It is fairly easily managed by physical and chemical means, though the soil seed reservoir means followup treatments are necessary.

Description:

Cenchrus echinatus is an annual, branched and somewhat tufted grass that grows up to 1 m tall. It is erect at the base, with fibrous roots and has the ability to form mats. The blades are either smooth or slightly hairy on the upper surface, smooth on the lower surface and are up to 9 mm wide. The inflorescence are spike-like, up to 10 cm long and has up to 50 or more spiny burrs (5 - 7 mm long), which are well-spaced, subsessile with 2 - 4 spikelets. These burrs are easily detached.

Occurs in:

Agricultural areas, coastland, range/grasslands, riparian zones, ruderal/disturbed, urban areas, wetlands.

Distribution Map:

Habitat description:

Cenchrus echinatus can grow in a variety of conditions, and grows readily in tropical and temperate zones. Though it is often associated with dry, sandy soils, C. echinatus thrives in moist conditions where it is generally longer lived and can grow much larger. It readily colonises open ground and is known to invade agricultural areas, riparian zones, disturbed areas, sand dunes and other coastal areas, pasture, road sides, gardens and swamp margins.

General impacts:

Cenchrus echinatus infests dry areas especially along leeward coastlines. Burs are a nuisance for people. They are reported as dangerous for hatchlings of seabirds on the Northwestern Islands. A prolific seeder, it forms mats and can displace native grasses.

Geographical range

Native range: A native of tropical America

Known introduced range: weedy or invasive in most tropical and temperate countries, introduced into the Mascarene Islands, Polynesia, and Northern Australia.

Management:

Physical/Chemical: Physical and chemical management techniques have been found to be effective against Cenchrus echinatus. Physical measures include hand-pulling individual plants, which can either be done on its own or following spray treatment with herbicide. Effective chemicals include glyphoshate, chlorazifop, altrazine and benfluralin. Follow up procedures are necessary due to the seed reservoir of C. echinatus. It has been noted that preemergence herbicides could be useful.