Wireweed (Polygonum aviculare)

Photo: (c) Rasbak CC BY-SA 3.0 license

Family: Polygonaceae

Photo: (c) Evelyn Simak CC BY-SA 2.0 license

Growth Habit: Wireweed is a scrambling, prostrate weed able to grow in a wide range of soils. Very young plants look like fine grass.  Young plants may be erect, but this species usually has a spreading and scrambling habit, overgrowing surrounding vegetation.  It has small alternate leaves that are hairless like the stem. This tough stem, which can grow up to 1 m in length, has longitudinal ridges. There is quite a deal of variation between plants growing in different conditions. Some plants may be a darker green or blue/ green and have smaller leaves (15 to 29 mm), whilst others may have leaves that measure 30 to 50 mm and be much lighter in colour.

Type of Plant: Wireweed is an aggressive, fast growing annual.

Photo, cropped: (c) Hugh Knott CC BY-ND 2.0 license

Flowers: There are 2 to 5 tiny flowers per cluster which are white with a possible hint of pink. These measure about 2mm in diameter and are located along the stems.

Fruit/Seed: A few tiny seeds are produced per flower.

Dispersal: Reproduction occurs purely by seed, with germination mainly in spring and early summer.

Distribution: Widespread throughout the State, including cropping and grazing lands, gardens, roadsides and waste places.

Status: Undeclared in Tasmania.

Weed Impact:

  • A major weed of arable crops. Its tough wiry stems often interfere with harvesting operations.

For further information contact the Department of Primary Industry, Parks, Water and Environment, Tasmania.

Control Methods:

  • Herbicide. For roadsides, waste areas and pastures, herbicides registered for use include glyphosate, metsulfuron, MCPA and dicamba. Contact DPIPWE for specific recommendations for in-crop use.

N.B. Always check the herbicide label before use.