Planting Techniques to Attract Butterflies
There are 13 species of butterfly that are established in New Zealand and three of those are found only in South Island. The elegant Helm’s butterfly is restricted to open swampy glades in upland beech forest and is unlikely to be found in the Coromandel. The ubiquitous Cabbage White unfortunately is found here, as it is in most of the rest of the world, but it will take no further part in this discussion. So that leaves us with eight species that could be encouraged in the Coromandel region.
Species |
Wing span |
Caterpillar food |
Habitat in the Coromandel |
Monarch |
60 mm |
Swan Plant (Asclepia) |
Common; Garden |
Red Admiral |
50 mm |
Nettle |
Not common; Garden |
Yellow Admiral |
45 mm |
Nettle |
Rare; Garden |
Painted Lady |
45 mm |
Thistle |
Very rare; Garden |
New Zealand Blue |
24 mm |
Grasses & clovers? |
Common; short pasture |
Common Copper |
30 mm |
Muelenbeckia |
Rare; rough pasture & scrub |
Dark-banded Copper |
30 mm |
Muelenbeckia |
Very rare; forest edges |
Small Copper |
20 mm |
Muelenbeckia |
Unlikely; mainly Southern rough pasture & scrub |
To encourage butterflies, we need nectar for the adult butterfly, the correct foodplant for the caterpillar and awareness that encouraging any species can have complex repercussions to an ecosystem.
Adult butterflies are undiscriminating feeders. They sup the nectar of any flower they can find. A solution of 10% honey dissolved in water and soaked onto a cotton pad is a good alternative food source. The longer lived species need some extra nutrition and enjoy soft fruit like bannana. Caterpillars tend to be very fussy feeders and are usually restricted to just one genus of plant. In many parts of the world, the concept of encouraging more butterflies is fraught with the danger that the caterpillars might also feed on other plants that have some kind of economic or environmental significance. That is unlikely to happen with the few species of butterfly that can be found around the Coromandel because all our butterfly caterpillars have a very restricted diet (except for the Cabbage White…and we are still not going to talk about that one).
Butterfly caterpillar foods can be divided into 5 groups:
- Asclepias (the Milkweeds) for the Monarch Nettles for the two Admirals Thistles for the Painted Lady Muelenbeckia for the three Coppers
- Pasture grasses for the NZ Blue
The Monarchs, the Admirals and the Painted Lady are strong flying insects that have migrated more or less around the world. Their biology and ecology is well understood from studies around the globe. It is difficult to envision circumstances where the caterpillars of these 4 species could cause a nuisance because they have such specific food plants, but it is possible that over-enthusiastic planting of native nettles could create a problem. The swan plant that is so widely planted in gardens for Monarchs shows little signs of spreading into the wild.
The NZ Blue butterfly is so well established in the Coromandel that its encouragement is hardly an issue. Unlike other pasture-eating insects such as the Field Cricket, the caterpillar is not regarded as a pest.
The three NZ Copper butterflies have caterpillars that feed almost exclusively on Muelenbeckia. They have been seen feeding on Peperomia (kawakawa) so it is possible that other plants could be eaten. There is no indication that either the coppers or Muelenbeckia could be harmful environmentally and no likelihood of them being harmful economically.
Monarchs
There has been so much written about rearing Monarch butterflies that I won’t add much more. If you plant Swan Plants in your garden in the Coromandel you will almost certainly get some caterpillars. But there can be a very high level of predation from wasps, mainly the Asian Paper Wasp and the German Wasp. You either need to protect your Swan plants with wasp-proof netting or bring the half-grown caterpillars inside and feed them every few days with fresh swan plant twigs. Incidentally, it is possible to freeze swan plant leaves. Caterpillars are quite happy with thawed out leaves.
The Monarch Watch site gives more information: www.monarchwatch.org .
Red Admiral & Yellow Admiral 
These two closely related colourful butterflies are both found from Europe across Asia to the Pacific. The New Zealand Red Admiral is regarded as a different species from the European only because of the blue centres to the black spots on the rear wings. Their behaviour and food, however, are identical.The Admirals (or Admirables, as they were originally known…the name has nothing to do with ornate naval uniforms or maritime migrations) are undoubtedly one of the prime species that we want to attract to our gardens. Twenty years ago the standard recommendation would be to plant some Buddleia bushes to feed the adults and find an obscure corner of your garden where nettles can grow for the caterpillars. It’s not so simple in 2002. Both Buddleia (Buddleja davidii) and the introduced Perennial or Stinging Nettle (Urtica dioica) are regarded as Noxious Plants under the BioSecurity Act 1993 and it is an offence to propagate or distribute them (sec. 52 & 53). However all adult butterflies are pretty undiscriminating about which nectar they sup. Any nectar rich bush will do and we are allowed to grow the hybrid Buddleias. You just need to make sure that the variety you choose has nectar as well as good looking flowers.Finding a food source for the caterpillars is a little more tricky. If you happen to have some European stinging nettle on your section then the Admirals will probably already have found them. But nettles spread like mad on any disturbed ground and will grow out of control quite easily. Not a pleasant plant to have around…the sting from a European nettle can hurt as much as a bee sting. We have six species of stinging nettle native to New Zealand that will act as alternative food plants. Three of these are found in the Coromandel area.
- The endemic Tree Nettle or onga onga (Urtica ferox) grows to 2m and favours coastal and lowland forest margins. Yellow Admirals appear not to feed on this.
- Urtica linearifoli is also endemic but is a straggling vine-like plant growing to about 2m long in swampy areas, particularly with NZ Flax. It is sparsely supplied with stinging hairs.
- Urtica incisa is about 60cm tall and found in forest glades and margins throughout NZ & Australia. It is sparsely covered with stinging hairs.
I have never encountered a Yellow Admiral in Cape Colville but see about 4-10 Red Admirals every year, so they could be feeding locally, or they could have just flown across from Auckland for the day, as one does. Both the Admirals are strong fliers, and many of the Yellow Admirals found in New Zealand could actually be wind-blown migrants from Australia.
Painted Lady 
The Painted Lady is another very attractive butterfly, closely related to the Admirals and also widespread from Europe to the Pacific. Most years small migrating swarms arrive on the west coast of North Island from Australia but they do not appear to have established a breeding colony here, even though the food plant of the caterpillars is thistle, which cannot be that hard to find. The adults are most likely to be found sunning themselves on warm rocky hillsides with low growing nectar plants but, like the Admirals, frequent gardens and are attracted to bushy nectar plants such as Buddleia.
New Zealand Blue
Between January and March most dry sunny hillside grasslands in Coromandel have swarms of these endemic butterflies. Any pasture management programme that encourages grazed grass and low growing nectar rich plants such as clovers and trefoil will support this species. Traditional NZ hill country pasture management involves spreading phosphate fertiliser to encourage the growth of clovers and other legumes. In turn, they produce the nitrates that grass needs to grow and which cattle need for protein and growth. It’s a three step process…fertiliser for the clovers, which feed the grass, which feeds the stock.
To encourage NZ Blues in your section, you need an area of shortish grass…it cannot just be left to grow rank, but a lawn mower probably cuts the grass too short. A scrub cutter 2 or 3 times a year might be the answer. Don’t use nitrogenous fertiliser as it will inhibit the nectar-rich legumes and clovers, but do apply a little phosphate fertiliser. Scatter some legume seeds, particularly the taller ones such as bird’s foot trefoil, lotus and white sweet clover (Melilotus alba)
The Coppers
The New Zealand Copper butterflies become more common as you travel south and the Coromandel is approaching their northern limit. The caterpillars of all three species feed on Muelenbeckia, which is a rather rugged genus of plants accustomed to inhospitable coastal locations and lowland forest. Of the eight species found in New Zealand, 4 are restricted to the sub-antartic islands and only two are found in North Island. Planting Muelenbeckia australis and M. confusa in broken land, forest margins and particularly on coastal cliff areas will provide food for the caterpillars. The Muelenbeckias are regarded as good nursery plants to protect plantings of coastal trees such as Pohutakawa. The adult butterflies, like most butterflies, are undiscriminating feeders on any source of nectar.
