Gomphocarpus cancellatus
ASCLEPIADACEAE
Broad leaved Cotton Bush. Wild Cotton Bush
Native to South east Africa. Introduced into Australia as an ornamental garden plant. Now an environmental weed in Western Victoria & Southern South Australia of waste lands & also an invasive plant of conservation areas. This photo was taken on the foreshore region of Lady Bay. It is the larval food plant of the Wanderer Butterfly (Danaus plexippus), also an introduced species.
Upright stems, 0.5 – 1.5m tall with an underground fibrous root stock.
Broad egg shaped leaves with rounded bases & a pointed tip, 4 -7 x 1. 5-3cm, slightly fleshy, green above & paler below with a conspicuous whitish mid vein.
Attractive flowers are grouped in a dense ball with pale mauve, green or greyish petals on the outside & 5 cream or white boat shaped lobes on the inside. Flowering all year round but mostly April to Aug.
The fruit or seed pod is an inflated pod with bristle like protrusions that will ripen from pale green to dark green sometimes with maroon stripes. When it is ripe it will burst open to release the black seeds each white tufted. Seed is long lived up to 5 years. It is dispersed by wind or water.
Wear gloves when handling this weed as the plant produces a white irritating sap.
Hand pull individual plants after rain when the soil is softened.
Cotton bush is poisonous to stock but is rarely eaten.