Family: Fabaceae
Common Name: Kudzu vine, Kudzuranker
Category: proposed 1a (NEMBA), 1 (CARA)
Description
Pueraria montana (Lour.) Merr. var. lobata (Willd.) Maesen & S. M. Almeida ex Sanjappa & Predeep is a perennial, long-running, hairy vine up to 18 m high, somewhat woody, with tuberous roots, leaf stalks and stems covered with rusty-brown hairs. Leaves light green, finely hairy, 3-foliolate; leaflets with entire margins or shallowly lobed, 70-150 mm long, abruptly sharp-pointed but not bristle-tipped. Flowers, reddish-purple, fragrant, in spikes up to 300 mm long, flowering time from March-April. Pods flattened, clustered, 50-130 mm, covered with long rusting-brown hairs.
Distribution
Native to southern Japan, southeastern China and Eastern Asia. It is invasive in other countries such as the US, where it was introduced around 1870 for a Centennial exhibition and later promoted as a forage crop and planted widely along highways for erosion control. It is also invasive in Canada.
How it spread
Kudzu vine is an aggressive invader, spreading mainly by vegetative means, using its stolons (runners) that root at the nodes and also by rhizomes. As many as 30 vines may grow from a single crown or single root. It also produces seeds of which few are viable. Other means of spread may be by wind, birds and mammals as well as water.
History in South Africa
Kudzu vine was probably introduced into South Africa as an ornamental and for erosion control. The earliest record at the Pretoria National Herbarium is of a specimen collected in Mpumalanga at Brookland State Forest in 1985 and has since spread to Schagen valley between Sudwala and Rosehaugh. It has been recorded in Limpopo and KwaZulu-Natal.
Environmental and economic impacts
Kudzu vine forms dense mats over the ground, debris, shrubs and trees by twining around objects. It invades forest margins and gaps, riverbanks and moist areas. It smothers desirable plants and causes them to collapse. Kudzu vine is a legume, thus can fix nitrogen and enhance the soil fertility. This may also affect indigenous species. It is very drought tolerant which makes it more aggressive. In the US kudzu vine has taken over many areas, especially the southern parts of the country, and control amounts to billions of dollars. Farmers need to be aware of kudzu vine as it can be mistaken for soybean when it is still young, and it can be an alternate host for soybean rust.
How to eradicate
The registered herbicide for kudzu vine is Triclopyr. The plant can also be killed by uprooting the root crown and all rooting runners and these must be destroyed. Repeated mowing or heavy grazing can exhaust plants and assist with control measures.
What can you do to help?
Report sightings of these plants to the Early Detection and Rapid Response Programme (EDRR) team. We will need to know its locality (the exact locality, supply any landmarks of GPS information if possible).
Contact details
Alex Marsh
Email address: alienplants@sanbi.org.za
Tel: 021 799 8743
Photos:
Lesley Henderson © ARC-Plant Protection
Bongani Mashele
References
- Henderson, L. and Musil, K.J. (1987). Plant Invaders of the Transvaal. Department of Agriculture and Water Supply. Pretoria, South Africa (garden thug, weed)
- Bromilow, C. 2010. Problem plants and Alien weeds of South Africa. Briza publications. South Africa
- USDA Forest Service, Forest Health Staff, Newtown Square, PA.