Brisbane Rainforest Action & Information Network

Cat's claw creeper (Macfadyena unguis-cati)

In this issue we continue our series on exotic vines that degrade rainforest communities. One of the most destructive exotic vines is Cat's Claw Creeper (Macfadyena unguis-cati). Cat's Claw Creeper is a problem weed in numerous remnant rainforest patches around Brisbane. Thankfully, most of these infestations are localised to smaller areas; even so, this vine species can have a devastating impact on rainforest vegetation, especially in the smaller, more vulnerable remnants (for example along the scrub sections of Oxley Creek).

Cat's Claw Creeper is a highly vigorous South American vine that was introduced to Australia as a garden ornamental. It is easily identified by its opposite leaves (each has two leaflets) and the three-clawed tendril growing from each leaf stalk.The name "Cat's Claw" derives from this clawed tendril which the plant uses to climb.

The root system of the plant is quite extensive and produces a large tuber at about 50cm intervals along the lateral roots. Each tuber produces individual climbing runners that climb all surrounding vegetation.

These runners can also grow as a ground cover along the forest floor of scrub remnants and can form a thick carpet of stems and leaves which chokes out small existing plants and stops germination of all species. The large climbing stems reach to the top of the rainforest canopy where, through a combination of weight and shading, they can cause the eventual death of the largest canopy trees. (As an example of this, at the Wingham Brush in central NSW, an infested tree with a girth measuring 1.5m had 560 individual vines climbing on it. Some of the larger vines had diameters of 15cm. This tree was killed by the Cat's Claw infestation).

Cat's Claw Creeper is highly tolerant of low light situations, though it is much more vigorous in sunny gaps and on the edge of remnant areas. The ornamental appeal of the plant is obvious when it flowers as it produces a large, bell-shaped, bright yellow flower. The flowers can also aid in the identification of Cat's Claw affected areas, as they are visible from some distance away. Seed is produced in prodigious amounts in long, thin, brown seedpods. This seed is spread by wind and water. A large number of the infestations in Brisbane occur along the creek systems where the seed source has obviously come downstream during floods and during normal stream flow.

Control Methods

Control of Cat's Claw depends on the use of herbicide. Hand control is not practical except on a very small infestation. The tubers that the plant produces can grow up to 40cm long and are incredibly difficult to dig out because they tend to break off when you are trying to pull them out. Each tuber must be dug out completely and this involves causing massive disturbance at the infested site, with root destruction of the surrounding native vegetation.

Chemical control of the vine is a much more practical and achievable goal, especially for large infestations. The stems of individual vines can be cut close to the ground and the basal end should be painted with 100% Glyphosate. The poison translocates down the stem and into the tuberous root system thereby killing the entire plant. The top section of the severed vines can be left on the tree if the vines are not too large. Otherwise they should be removed from the trunk and bundled together. Some regrowth from the severed vines is likely to occur. Any regrowth can be foliar sprayed with Glyphosate 1:100 or up to 1:50 (plus surfactant, like Codacide Oil).Ground cover carpets of Cat's Claw can also be foliar sprayed to great effect. Infestations treated in this way do not need to be cut and painted. In all spraying operations be very careful to avoid spraying existing native plants and watch for any spray drift.

Ken McClymont