Scientific name: Chenopodium album
  • Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Erect annual weed which can grow up to 2 m in height but is usually much smaller
  • Leaves on a stalk, green-grey in colour, mealy and coarsely toothed
  • Lower leaves tend to be broader lance-like in shape and approximately 7 cm long by 4 cm wide. Upper leaves narrower and sometimes toothed
  • Stems angular, branched and brownish-yellow with parallel reddish or green stripes
  • Flowers very small and pale green, in stalkless, terminal and axillary clusters. Flowering occurs from December to May
  • Seeds are circular, 1 mm in diameter and glossy black in colour
  • Root system is fibrous and extensive.

Origin and habitat

  • Originally from temperate Eurasia and North Africa
  • Distributed throughout the North, South, Stewart and offshore islands of New Zealand
  • Common weed of gardens, crops, construction sites, gravel pits and waste areas, and often found in newly-sown pasture
  • Prefers well drained conditions
  • Killed by frost
  • Can grow in soils, where pH ranges from strongly acidic to alkaline, and tolerates high or low rainfall conditions.


  • Increasing daylight and warm weather stimulates reproductive development
  • Each plant produces tens of thousands of seeds.
  • Seeds can remain viable in the seed bank for many years. In one case seed viability was 23% after 20 years of burial below the soil surface
  • Seeds are dispersed by cattle, sheep, pigs and birds, either by ingestion and passage through the gut or on mud stuck to hooves or feet. In one study germination of fathen seeds which passed through birds ranged from 32 – 100 %
  • Seeds are also spread by agricultural machinery and vehicles.

Impacts on pasture / crop

  • Considered in many countries to be one of the most serious weeds of a range of crop species e.g. potatoes, sugar beets, kale, carrots, soybeans.

Impacts on livestock

  • Toxic to both sheep and swine, if eaten in large quantities, most likely due to its high levels of oxalic acid.


  • Seeds are an important source of food for birds
  • Fathen has been used as a vegetable and grain since the Stone Age. It is closely related to the South American plant that produces quinoa.

  • If cut or trampled during the early stages of growth the plant will not survive.

Herbicides used to control fathen in pastures include the following:


Active ingredient When to apply Residual effect Grass damage Clover damage
2,4-D ethylhexyl ester Early spring before 4 leaf stage for butyic formulations and bentazone. Early spring before 6 leaf stage for chemicals other than butyic formulations (MCPB, 2,4-DB) and bentazone. Moderate No Slight
2,4-DB Moderate No Slight
bentazone Slight No No
bentazone and MCPB Slight No Slight
chlorsulfuron Moderate Moderate Severe
flumetsulam Slight No No
MCPA Moderate No Slight
MCPB Slight No Slight
MCPA and MCPB Moderate No Slight
tribenuron-methyl Slight Slight Moderate

Consult your farm consultant, industry rep or New Zealand Agrichemical Manual for more information about chemical control.

  • Bassett IJ, Crompton CW 1978. The biology of Canadian weeds. 32. Chenopodium album L. Canadian Journal of Plant Science 58: 1061-1072.
  • Popay I, Champion P, James T 2010. An illustrated guide to common weeds of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand. 416 p.