If you run out of milkweed (swan plant) probably the best alternative food is a noxious weed found especially in the north of New Zealand, Araujia sericifera (sometimes called cruel vine, choko vine, moth vine). Do not grow this plant – it is illegal to cultivate or encourage it – but you can often find it growing along back fences, beside railway lines or on abandoned properties.
Other foods that people have tried with some success are Tweedia (Oxypetalum caeruleum), fresh pumpkin, cucumber and marrow. But it is important to remember that you need to plant NOW for the caterpillars the following year – it is expensive and impractical to buy “food” for your caterpillars at garden centres. Often these plants have been sprayed.
Pumpkin as an alternative food
Below is a photograph from Marilyn Corbishley of Taradale, Napier. Marilyn’s excellent video footage of the Monarch in all stages is available on a DVD for schools and other interested groups.
When we mentioned that Marilyn feeds her late stage larvae on pumpkin in an emergency to other Monarch-lovers overseas, no0ne had heard of this before. It is only in the very last stages of the caterpillar’s life that you can feed it pumpkin instead of milkweed – otherwise the caterpillars will not form properly.
