EXOTIC VINES: AN ENVIRONMENTAL HAZARD

EXOTIC VINES: AN ENVIRONMENTAL HAZARD

Published in The Nimbin Good Times. June 2004.

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David McMinn

Exotic vines are one of the most serious weed threats in the Northern Rivers and south east Queensland. They climb up tree trunks into the canopy, where the weight of the vine foliage can result in limb breakage. They can also completely smother the tree or, in very serious infestations, they can smother the whole forest. Gardeners should avoid planting exotic vine species unless they know for certain that they will not create a weed problem at a later date. Some of the most serious vine weeds in the region have been listed. All of these were originally introduced as garden plants for the inane reasons that they were pretty, unusual or had scented flowers. Gardeners failed to realise the huge the environmental problems their garden plants were going to create.

It is essential that people learn to recognise potential vine weeds. If they start to appear in their area, they can get rid of them quickly. A few plants are easy to eliminate. However, once a vine species becomes established in an area, it will be very difficult (impossible?) to eradicate. Madeira Vine is growing at the back and front of our property at Blue Knob (NSW). When the vine is flowering and most conspicuous in autumn, I go searching along the creeks and poisoning any small plants. To date it has not established on our property, but only because I have been very diligent every year.

If exotic vines are a problem in your area, fast growing tree species should be planted that shed their bark, thereby preventing the vines climbing up into the canopy. This includes various gums (Eucalyptus species) and Brush Box (Lophostemon conferta). These trees will need protection from the vines until they are large enough to cope. Such tree species can also be planted on the borders of rainforest plantings to provide a buffer. This would help prevent the vines overwhelming the more susceptible rainforest trees. Additionally there are a number of Native Vine Species that may be grown as an alternative to exotics.

Some exotic vines do not present difficulties, such as Passionfruit (Passiflora species), edible Grapes (Vitis species) and so forth. Alas, I cannot offer much advice on this, as I have never bothered with growing exotic vines. My only blunder was Honey Suckle in the mid 1980’s. I am still trying to get rid of it from our garden – very unsuccessfully.

Gardeners need to be aware about the dangers of planting exotic vine species. It is so easy to make mistakes and leave the our beautiful environment saddled with yet another serious weed infestation. DO NOT PLANT EXOTIC VINES UNLESS YOU ARE ABSOLUTELY CERTAIN THEY WILL NOT GO FERAL OR CAUSE ENVIRONMENTAL PROBLEMS.

EXOTIC VINE SPECIES	COMMENTS
Madeira Vine (Anredera cordifolia)	This is a rapidly growing invasive vine. Fortunately it does not seed in Australia and can only spread vegetatively. Bits of the plant break off during floods and take root further downstream. Thus, it is usually found along creeks. It can also be transported human activity and people should not introduce the vine to new areas.
Moth Vine (Araujia sericifera)	Moth vine is easily recognised by its distinctive white flowers and a milky sap when cut. Alas, it is becoming increasingly common in the area. The vine traps moths in its flowers and kills them. Hence the common names Moth Vine and Cruel Vine.
Dutchman's Pipe (Aritolochia elegans)	The magnificent, endangered Richmond Birdwing Butterfly will lay its eggs on this vine, but the young caterpillars cannot eat the leaves and die. NEVER PLANT THIS VINE. Instead plant the Ricmond Birdwing Vine (Aristolochia praevenosa) to attract the Birdwing Butterfly to your garden or rainforest planting. This is the only food source for this beautiful insect and you will help ensure its long term survival.
Legume Vines (Species from the families: Caesalpiniaceae, Fabacea & Mimosaceae.)	Exotic legume vines (Glycine, Siratro, Desmodium, etc) were introduced into the region as cattle feed in the 1960's and 1970's. They have become a serious pest in some areas. The only legume vine that could be recommended is Shaw Creeping Vigna (Vigna parkeri). It only climbs weakly and is excellent for growing amongst grasses in orchards and pasture.
Morning Glory (Ipomea species)	Various species have become established in certain areas of the region, enveloping trees and degrading forest biodiversity.
Kudzu (Pueraria lobata)	This is a spreading legume vine species. Flowers vary in colour from purple, blue and pink. It was promoted by Permaculture in the 1970s for its edible tubers.
Honey Suckle (Lonicera japonica)	A rampant vine, originally planted for its sweetly scented flowers. It can easily get out of control and should not be planted. Alas it is still being sold by the nursery trade.
Cat’s Claw (Macfadyena unguis-cati)	Another rampant vine, which is easily distinguished by its beautiful chrome yellow flowers in spring. This species is enveloping the River She Oaks along Goolmangar Creek (below The Rocks) and slowly killing them.
Black-Eyed Susan (Thunbergia alata)	This vine has a distinctive yellow flower with five petals and a black centre. It can easily escape from the garden into the local environment, where it can be very invasive.
Sky Flower/ Blue Trumpet Vine (Thunbergia grandiflora)	This is still being sold by the nursery trade unfortunately. It is a beautiful vine with pale blue flowers. Despite its attractiveness, it should not be planted because of its weed potential.