Pueraria lobata

Also known as: Kudzu, “Mile a minute” vine
Family: Fabaceae Photo © Big Scrub Rainforest Landcare Group
By Barbara Stewart

In Georgia, the legend says that you must close your windows at night to keep it out of the house. The glass is tinged with green, even so. (From the poem "Kudzu" by James Dickey).

Kudzu Pueraria lobata is a rampant leguminous vine which cloaks trees and spreads rapidly across the ground. Its large leaves with three lobed leaflets are distinctive. Under the ground is a huge tuber, growing metres deep and a source of arrowroot. In Asia it is used to produce a variety of tofu, and various parts of the plant have medicinal uses. First introduced to the USA in 1876 for its ornamental purple scented flowers, it was later promoted there for soil conservation and as a forage crop. Subsidised plantings and an emotive campaign which included a Kudzu Club and Kudzu Beauty Queen quests saw the plant widely established across the southern states before it was recognised as a weed. By this time the soil was saturated with hard-coated long-lived seed, and up to 3 million ha of ground was infested. Search the web for crazy kudzu stories, including frightening pictures of houses and car bodies engulfed by the vine at www.jjanthony.com/kudzu/

In 1951, the NSW Agricultural Gazette announced the results of trials of the vine as a forage crop, noting that cattle grazed on it with great relish. Fortunately, it did not catch on in a big way, though plantings were carried out in Wilsons Creek in the ensuing years. Some of the vines persisting today originate from those early plantings.

In our valleys, kudzu can be discerned growing with Morning Glory on the roadside to the west of the school, and the patch continues up the hill where the Green Corps team have made a start on containing it. Another small patch is on Upper Wilsons Creek Road before the first crossing and opposite the green and yellow mail box. The vine is deciduous so the leaves are yellowing and falling this time of year ( written in June).

The largest infestations on the north coast are at Limpinwood in the Tweed, and Coopers Lane, Main Arm. In total, around 10 patches have been documented between Ballina and the border, with a further cluster of about 6 sites in the Coffs Harbour/Bellingen area. As we have a relatively small number of localised sites, kudzu is not likely to spread except by vegetative growth, so long as it is not deliberately planted. Seeds are not readily dispersed and most new infestations in the US arise from movement of contaminated soil.

In the US, the scale of the problem means that heavy chemical applications are almost inevitable. However, continued grazing and mowing eventually exhaust its underground reserves. Persistence is the key, and even chemical applications require many treatments. NSW Agriculture is currently conducting trials in the Bellingen area, and bush regenerators are applying their skills and ingenuity at various sites. Some firm recommendations for control in local conditions will hopefully emerge, and we can look forward to sleeping with open windows without fear.

Eradication Techniques

Organic

Slash, or diminish by shading site

Chemical

Cut, Scrape and Paint (Glyphosate 1:1.5)

Spray (Glyphosate 200ml/10L + LI 700 50ml/10L or Metsulfuron Methyl 1-2gms/10L + Agral 2ml/L)

 

Kudzu gardening tips – from the southern US

  • Always plant kudzu at night – otherwise angry neighbours may see you and throw rocks at you
  • Kudzu can be grown organically – just let the pests get out of the way of the kudzu as best they can
  • Apply motor oil as lubricant. This reduces friction as it powers across the ground and lessens the risk of fire
  • Blocks of concrete make good mulch. After a temporary setback, plants will regard the mulch as a challenge and reward you with redoubled determination.