In NZ the natural food species of the Monarch (Danaus plexippus) larvae is the Asclepiadiae family – milkweed which includes swan plant (Gomphocarpus fruticosus) and giant swan plant (G. physocarpus) as well as Asclepias species such as tropical milkweed/bloodflower (A. curassavica). The tropical milkweed comes in two colours -scarlet (which has a gold centre) and gold (all yellow).
The term ‘milkweed’ can be confusing – but a Fact Sheet on this is available. The Monarch Butterfly NZ Trust will be able to help you with seed of the giant swan plant and tropical milkweed, each packet is $5.
Larvae in their latter stages can be also fed on a noxious weed which is sometimes called moth vine, cruel vine or kapok plant (Araujia sericifera) as well as cucumber, pumpkin and courgette – but only when they are ten days old or more than 2cm in length. This weed is on the banned list in some regions – check with your regional council.
Adult butterflies will feed on any plant giving nectar. They usually choose flowers with bright colours, purples, pinks and blues. Hebes are very popular. There are more listed in our forum – click on the link on the homepage to go there. There is a poster showing many nectar plants available from the MBNZT. See it here.