Chickweed

Cirsium arvense

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.

Cotyledons:

• Light green
• Apex pointed
• Base rounded, stalked

Leaves:

• Opposite in pairs
• Ovate with pointed tip

As it matures, chickweed with its low growing habit will spread out to 40 cm. The round stems are thin, branched and weak being easily broken. The leaves are soft, green and up to 2 cm long. The leaves are in opposite pairs on hairy stalks.

White star-like flowers are produced on slender stalks. The flowers are 1 cm in diameter with 5 deeply divided petals. Chickweed grows very rapidly and can produce seeds within 6 weeks of germination. A plant can produce 10-20,000 seeds.