Fathen

Chenopodium album

Fathen (Chenopodium album), pronounced fat-hen and sometimes called fat hen, is one of the most serious weeds of cropping throughout New Zealand. It is an annual that germinates in the spring and early summer and then dies off in the autumn with frosts. Fathen is an extremely vigorous weed that can quickly outcompete and smother crops. An upright plant that can grow to 2 m tall and is a prolific seeder.

Fathen (Chenopodium album) is a spring germinating annual weed that is regarded as one of the most pernicious weeds in New Zealand. Very common and capable of growing up to 2 metres tall, fathen is a seriously competitive weed in all cultivated crops. Fathen is regarded as the most competitive weed in beet crops globally.

Cotyledons:

Long, slender, oblong shape
Apex rounded and stalked

Leaves:

Oval to egg shaped
Sugar-like crystals on new leaves

As plants mature they have an upright erect growth. Can grow up to 2 metres tall but in adverse conditions can flower as plants less than 10 cms high.

Leaves are grey-green, of variable shapes, coarsely toothed with stalks. Multiple seeds are produced prolifically on stems.

A mature plant can produce up to 20,000 seeds. Susceptible to frost so only grows through the spring and summer.

Related Pests

Chickweed

Stellaria media

Chickweed (Stellaria media) is a widespread, very resistant weed, it is found in the North and South Island in areas of cultivated land and roadsides. Commonly seen in winter, it does not favour drier conditions. It is a problem in small grain crops such as barley, causing up to 80% yield losses. It a low growing spreading annual (up to 40 cm) with, light green soft leaves, (lighter underneath) up to 2 cm long. The leaves are in opposite pairs on hairy stalks. Flowers are white, about 1 cm in diameter, with 5 deeply divided petals that appear to be 10 petals. Chickweed flowers and sets seeds simultaneously. The seeds are contained in green egg-shaped capsules, and one plant produces about 15,000 seeds, which remain capable of germination in the soil for up to 5 years.

Broad-leaved Fleabane

Conyza sumatrensis

Broad-leaved fleabane (Conyza sumatrensis) is an annual or biennial weed that is common throughout New Zealand on roadsides, wasteland, orchards and vineyards. In recent years it has been increasingly seen in pasture. It starts as a rosette that then forms a vigorous upright stem up to 1.8 metres tall. The stem branches at the top producing copious quantities of small green seed heads.

Black Nightshade

Solanum nigrum

Black nightshade (Solanum nigrum) is a significant weed in arable and horticultural crops but it is also common in disturbed pasture. Black nightshade is present throughout New Zealand but less so in the lower South Island. Distinctive black berries (7-10 mm) can be found on mature plants.