|Melkkruid Milk weed
Ants collecting the nectar
Kruger National Park
Asclepias fruticosa - A perennial, slender, erect shrub of up to 1.5 m. It is common in grassland and, being a pioneer plant, on disturbed ground. The inflorescence hangs and comprises up to 10 flowers, flowering Dec.-Mar. The waxy cream flowers develop into silk plumed seeds. The plant, when damaged, produces a bitter, poisonous sap.
It is often planted in gardens (it is frost-sensitive, requires full sun and well-drained soil, and should be regarded as invasive), particularly because it attracts butterflies (Monarch and Swallowtail), but also crab spiders, ladybugs, bees, wasps, ants and moths. Some feed on the nectar and the plant itself while others feed on the insects.The milkweed not only provides food for the adult Monarch butterfly but it also provides a nesting area for eggs and larvae. It can have a large deep root system once it becomes established and is then difficult to eradicate from gardens.
The plant is quite toxic because it produces a group of toxins known as cardenolides. The poisonous cardienolides protect the plant against herbivores. However, some animals are capable of eating the plant without ill effects. Thus the Monarch caterpillar (Danaus chrysippus) is among a select few creatures able to graze on the leaves of the milkweed. It manages to sequester and store the poisons, so that the butterfly into which it develops is protected from predators. The female Monarch butterfly lays her eggs on the underside of leaves, where they hatch in about 5 days; the young caterpillar chews its way out of the egg, usually eating the shell as its first meal.
Other names - UK cotton milkbush, fire sticks, narrow leaved cotton bush, shrubby milkweed, swan plant, wild cotton, white swan milkweed, swan plant milkweed, tennis ball bush, gendarmes weed - F faux-cotonnier - D Strauchige Seidenpflanze, Schwanen-Seidenpflanze - FI silkkiyrtti - S sidenört - NL zijdeplant - Afrikaans melkbos