David
McMinn
Exotic vines species
are one of the most serious weed threats in our region. They climb up tree trunks
into the canopy, where the weight of the vine can result in limb breakage. They
can also completely smother the tree or, in very severe infestations, they can
smother the whole forest. Gardeners should avoid planting exotic vines unless
they know for certain that will not be creating another huge weed problem. Some
of the serious vine weeds in the Nimbin Valley have been listed. They were
originally introduced as garden plants for the inane reasons that they were
pretty, unusual or had scented flowers.
Madeira Vine (Anredera cordifolia) is a rapidly growing invasive vine.
Fortunately it does not set 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 in the Nimbin Valley. It can also be
transported human activity and people should take care not introduce the vine
into new areas. Apparently, this species was only sold at two Channon Markets
in the 1970’s and it has now spreading throughout the Northern Rivers.
Moth Vine (Araujia sericifera) has distinctive white flowers and produces a
milky sap when cut. Alas, it is becoming increasingly common in the area.
The vine traps moths in its flowers and kills them, giving rise to the common
names - Moth Vine and Cruel Vine.
Cat’s Claw (Macfadyena unguis-cati) is a 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.
Honey
Suckle
(Lonicera japonica) is a rampant vine, originally planted for its sweetly
scented flowers. It can easily get out of control and should not be planted.
Fortunately it does not seem to set seed in the Northern Rivers.
Morning Glory (Ipomea species) has become established in certain areas
of the Nimbin Valley.
Sky
Flower (Thunbergia
grandiflora) 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.
Exotic legume vines (Glycine, Siratro, Desmodium,
etc) were introduced into the Northern Rivers for cattle feed in the 1970’s.
They have become a problem in some areas. The only legume vine that I could
recommend is Shaw Creeping Vigna (Vigna parkeri), as it only climbs weakly and
is excellent for growing amongst grasses in orchards and pasture.
It is essential that people in the valley are able 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. 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, 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). Young 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 vines
overwhelming the more susceptible rainforest trees.
There are a number of
local vines that may be grown as an alternative to exotics. All listed species
are native to the Northern Rivers and can be readily propagated from cuttings
and seeds.
Richmond Birdwing Vine (Aristolochia praevenosa)
is a strong growing vine, which is the only food source for the magnificent,
endangered Richmond Birdwing Butterfly. Planting this vine will attract these
beautiful insects to your garden or rain forest planting. NEVER PLANT the alien
Dutchman’s Pipe (Aristolochia elegans). The Birdwing Butterfly will lay
its eggs on this vine, but the young caterpillars cannot eat the leaves and
die. One of the nurserymen at the markets was horrified, when I told him that
he was contributing to the extinction of this beautiful butterfly. He withdrew
his Dutchman’s Pipe plants from sale locally and sold them to the nursery trade
in Sydney, where they would not cause a problem.
Water Vines (Cissus species) are too large and rampant for house
gardens. In rainforest regeneration plots, they will scramble up smaller trees
and smother them. Even so, they should be grown where possible as they are an
important food source for various birds. Thus, they are best used for climbing
over large rainforest trees or Camphor Laurels.
Guinea Flower (Hibbertia species) is
easily distinguished by its attractive yellow flowers. It is adaptable to harsh
conditions and can be used as a ground cover, scrambling shrub or vine
depending on the support provided.
Bower of Beauty (Pandorea jasminoides) &
Wonga Vine (Pandorea pandorana). These vigorous vines have very
attractive flowers that bloom over several months. They are widely grown as a
garden plants, but may need to be kept under control by regular pruning. Both
species require moist, well- drained soils.
Native Wisteria (Millettia megasperma) is a large rampant growing vine,
with attractive blue flowers in spring and hence the common name ‘native
wisteria’. It will need to be pruned regularly if used in the garden.
Red Passion Flower (Passiflora aurantia) has beautiful flowers. It likes
plenty of water and well drained soils, as well as full sun to set flowers and
fruit. It is not a rampant climber, making it suitable for house gardens.
Tetrastigma (Tetrastigma nitens) is
another rampant vine, but can be used for screening in large gardens. It will
need pruning to keep under control.
There are exotic vines that
do not present difficulties, such as Passionfruit (Passiflora species), Grapes
(Vitis species) and so forth. Alas, I cannot offer much advice on this, as I
have never bothered growing exotic vines. My big blunders were Honey Suckle and
the legume Vigna luteola in the mid 1980’s. I am still trying to get rid of
them from our garden – very unsuccessfully.
Nimbin gardeners must be
warned about the dangers of planting exotic vine species. It is so easy to make
mistakes and leave the local environment saddled with yet another serious weed
infestation. NEVER PLANT EXOTIC VINES UNLESS YOU ARE ABSOLUTELY CERTAIN THEY
WILL NOT GO FERAL OR CAUSE ENVIRONMENTAL PROBLEMS.
Copyright. © 2004. David McMinn. All rights reserved.