Zig-Zag Vine

Melodorum leichhardtii
Family: ANNONACEAE
I have no photo of this plant for you.
Instead, here is a picture of a lovely butterfly which blew into our garden today and hung itself up for the night in a sheltered spot. It left its wings outspread, and allowed us to approach for this photo, taken from just a foot away. (After dark, it folded its wings -perhaps to keep itself warm?)
It’s a four-bar swordtail (Protographium leosthenes).
We were delighted to see it, as these butterflies are uncommon hereabouts. The original population may have been quite substantial, but fourbars have a problem here, nowadays, finding a host plant that their caterpillars can eat. They need something from the Annonaceae family, and the only local native plant in that family is the zig-zag vine, a plant of rainforests and dry vine scrubs - environments that are being depleted by clearing.
Zig-zag vine is a good-looking plant, and could appropriately be grown in gardens more than it is. It begins life as a bushy scrambler, and only begins to climb when it is a few years old. In the rainforest it becomes a large vine, reaching up to the canopy.
If it can find nothing to climb on, it makes no complaint, simply settling down to make a fine specimen of a shrub. Potentially a large and bulky foliage plant, it can be used effectively as a screen on a substantial trellis, or for shade on a sturdy pergola.
“Melodorum” means “honey-scented”, because of the perfume that is released when the glossy dark green, wavy edged leaves are crushed. The fragrant, creamy-brown flowers come in pairs. See http://www.pbase.com/image/54220531
The shiny little seed capsules are orange, and look rather like strange waxy peanuts, with a “waist” between the seeds. See :
http://www.rainforestpublishing.com.au/index.php?href=botanical&dir=botanical_pages&subpage=view&ext=php&array_place=13&item_id=580#image_580
These capsules are hard on the outside but contain soft, edible, tangy-flavoured pulp. The alternative common names “acid-drop” vine and fruit salad vine give us some idea of the flavour and tell us why this plant is sold by nurseries which specialise in bushfoods. The pulp can be eaten fresh, and is also used to make liqueur.
Zig-zag vines grow slowly at first, so there’s no need to rush to get that pergola finished. Alternatively, gardeners might like to plant short-lived climbers such as native passionfruits on the structure, to keep them entertained while the zig-zag vine gets started.
As it starts to climb, the young zig-zag vine has a curious growth habit. Its young branches wrap themselves in a knot-like way around their supports, earning the plant an alternative common name - “knot vine”.
This is a drought-hardy plant, suitable for a waterwise garden.
Four-bar swordtails can also breed on custard apple plants (Annona reticulata), an introduced species from the Annonaceae family - but these frost tender trees are rarely grown up here.