Arctotheca calendula, Cape Weed

Image/s
Category
Herbs
Scientific Name
Arctotheca calendula
Common Name/s
Cape Weed
Weed Information

Threat: High threat agricultural weed.

Description: Annual rosette-forming herb with fleshy taproot. Individual plants grow to 80cm wide and 30cm high. The rosette grows through winter and flowers in late spring to early summer, before dying off. Forms mass display of yellow flowers on over grazed agricultural land.

Flowers: Produces a single yellow, daisy-like flower 2–6cm across at the end of stalks and 8–25cm long. Black to dark purple centre comprising many small flowers (florets). Mostly flowers spring to early summer.

Seeds: Small and covered with a dense pink-brown wool. A single Cape Weed plant can produce up to 4000 seeds which can remain dormant for two years.

Leaves: Leaves are deeply lobed with upper surface hairless to hairy, grey-green above, and pale green to white below, with woolly hairs. Basal leaves 5–25cm long and 2–6cm wide, on a stalk up to 6cm long. Upper leaves, if present, are stem-clasping.

Note: Seed spread by wind, water or in soil. Cape Weed develops a strong, highly-competitive rosette, choking out most other crop and pasture plants. Growth is enhanced by dry summers and overgrazing which leave bare soil in autumn. Can cause nitrate poisoning in livestock if eaten in large quantities.

Control measures: Hand weeding, spot spraying, slashing, mowing and re-vegetation.

Dispersal: Water, wind.