Plant Library: giant milkweed

This fast growing native shrub is useful for attracting wildlife to the garden.

Calotropis procera has distinct foliage and purple flowers. Getty Images / Gallo Images

Calotropis procera, Sodom apple, ushar, shakhr A fast growing, many-branched native shrub often considered a weed, Calotropis is immediately recognisable thanks to its upright stems, glaucous foliage and attractive purple flowers.

It is rarely cultivated because of its white latex sap, which is poisonous and can cause serious skin reactions. However, it is almost always found on disturbed ground near sites of current or former human habitation. Its presence is also thought to indicate the presence of groundwater.

The plant can easily reach three metres in height and is useful as a screen, as a background to other planting or as a source of temporary shade in a new garden. Calotropis can also be used permanently in very poor soils or in spots where nothing else will grow.

The seedpod is large and holds small seeds with thistle down tops that are caught in the wind when the pod opens. Seeds germinate quickly in good light but the plant can also be propagated from softwood cuttings. Alternatively, look out for small, unwanted plants on construction sites.

Calotropis is extremely tolerant of drought, wind and salt, and is useful for attracting wildlife into the garden, since it is an important source of food for butterflies and bees.