Milkweed is the common name for the Asclepiasgroup of plants; it is a large family with many different varieties. These plants contain a chemical called a cardenolidethat is toxic; it is in the milky substance that you seewhen you break a portion of the plant.This chemical actually makes the butterfly toxic to those who try to eat it.
Care needs to be taken when handling this plant as it can cause irritation to skin and eyes. Wash your hands after touching the plant and handle carefully so as not to break any branches. The toxic nature of this plant is far outweighed by its educational value.
The Swan plant gets its name from the seed pods that puff up and look like hairy swans. It is at this stage that they are picked and floated in water for Swan races! If the seed pods are left to mature on the bush, they will split open. Then floss in the centre of the pod that the seeds are attached to will fluff up, ready to be dispersed by the wind.
Running out of food is the worry forwhen you grow these plants, Monarch caterpillars are big eaters,and one or two can strip a small plant very quickly. Grow more than one plant, grow plenty in fact but don’t put them in the garden all at the same time. You need to provide fresh plants throughout the caterpillar’s life cycle. Plant some in the garden for the first visitors; keep the others protected from butterflies and other insectsthat will lay eggs with insect mesh or an old net curtain. Tuck it around the plant leaving space for air and water but no gaps for anything to get in. Leave them to grow and be ready for when the other plants has been stripped.
When you transfer the caterpillarsto a new plant, handle them with care and as little as possible; try using a soft bristle brush to coax them on and off the bush. Once this bush is empty of caterpillars’ trim back the bare stalks by a third. Coverto protect the plant and let it recover for use later. Keep an eye on it though as it is easy to miss eggs that may be hiding under leaves.
The Monarch is really an exclusive milkweed feeder, but that doesn’t mean it will feed on the other plants that are grouped under this common name e.g. Euphorbia as they are different altogether.
There is evidence that they will eat from the perennial Tweedia and the Moth (Kapok) Vine. This vine is a noxious weed please don’t plant one, look around. They can be found in and around gardens and waste lands.
In the later stages of the caterpillars’ life both pumpkin and cucumbers have been used, as an emergency measure. Wash and peel small portions, put in a tall container along with the caterpillars. Use a perforated lidand provide some twigs or branches for them to form their chrysalis on. Replace with fresh food regularly, don’t let them feed on mouldy food.
They like a well drained sunny position but are also happy with dappled shade that other shrubs provide.
Plant out of the wind and protect from spring frosts.
Interested in the Monarch Butterfly, check out the Monarch Butterfly Trust at monarch.org.nz