Giant Milkweed

My giant milkweed or Calotropis gigantea (syn Asclepias gigantea) is still flowering and finally starting to bush out now I’ve removed the pigeon pea that was smothering it. Also called crown flower, these plants are larval host plants for the Monarch butterfly (along with other milkweeds). But while the butterfly larvae may chow down on the milky sapped leaves, the plants are reasonably poisonous to humans. Like many of the plants in its family (Apocynaceae) it contains cardiac glycosides which affect the heart muscles, and while this compound can be used beneficially for medical purposes, excessive amounts can cause arrhythmia and death - which is why it made such a fabulous arrow poison!

The centre of the flower looks a lot like a royal crown!

Giant milkweed is native to Asia and tropical Africa and I saw loads of bushes along the roadside in Lombok, Indonesia, all covered in butterflies. The leaves are silvery and quite thick, so cope well with the heat and dry conditions. The flowers are purple and kind of waxy, with a raised crown in the centre (hence the common name crown flower). They were a favourite of the last queen of Hawaii (Queen Likiuokalani) and often made into leis - though the sap can be a skin irritant so that might have made for some fun while wearing them.

My giant milkweed.

A close relative of Calotropis gigantea, is C. procera, which is an environmental weed in the tropical areas of Australia and whilst it’s wise to keep an eye on C. gigantea in case it has the same tendencies, it doesn’t seem to seed as prolifically as C. procera, so hopefully will remain where it is planted!