11 July 2016

The Day of the Kudzu

It grows at the rate of a foot a day and it will quickly swamp anything that it can climb, from trees to power poles, even buildings.  It kills any flora it comes in to contact with, blocking access to light, growing over it and creating shading with its leaves - so denying its competition the ability to photosynthesize.  It now covers 7 million acres of the US Deep South and is continually advancing.  This is the day of the Kudzu.

The history of the Kudzu plant in the United States is almost as bizarre as the sight of the places it overwhelms with its foliage.  It is as convoluted and unexpected as something out of a Kurt Vonnegut novel.  It is the story of a chance but inexorable slow burn alien invasion which the author may well have relished.

We won’t do clever science fiction, however – we will start at the beginning.  The year was 1876 and the US was celebrating a century of independence from the British and held a Centennial Exhibition in Philadelphia.  They invited the Japanese to participate and they created a wonderful garden featuring flora native to their islands, entrancing visitors.

The plant which particularly captivated people was the kudzu.  An easy plant to grow it represented a quick fix for impatient gardeners, and both its flowers and scent were attractive. From gardens it spread but as its propagation was at the time limited to suburbia it was controllable – more or less.  Then someone discovered that goats and other livestock liked to eat it.

Image Credit Flickr User RobertMichalove
By the 1920s many garden nurseries were advertising kudzu as something approaching a miracle vine.  Plant it, stand back and pretty soon you have enough forage to keep your livestock going from here to eternity.  Plus, it was discovered that kudzu was an effective tool in the fight against soil erosion, a particularly fraught issue in a number of States in the Depression era.  Soon, kudzu was gaining ground in the Southeastern US where it had, by chance, discovered its optimum climate.

Image Credit Flickr User Mary Madigan
By 1953 the government was becoming aware of the issues that the unrestricted spread of kudzu might present.  It stopped any administrative promotion of the trailing vine but by then kudzu had already begun to spread to woodland and timberlands.

Image Credit Flickr User tinydr
Worried forest managers tried many different herbicides to stop the spread of kudzu.  While most were found to be ineffective unless consistently used over a number of years, one herbicide was even discovered to encourage the growth of the alien pea.  It seemed that they would never get to the root of the matter and discover how to kill off kudzu.

Image Credit Flickr User FullyFunctionlPhil
Perhaps a poor play on words but the root was where they should have been looking in the first place. Multiple vine nodes of kudzu can grow from a single root crown, a knot of tissue which can vary in size from a penny to a basketball, and which lies just below the ground.  If you remove the crown, kudzu dies as individual roots cannot produce vines.

Image Credit Flickr User mygothlaundry
Image Credit Flickr User gvgoebel
However (perhaps you have guessed already) there is a further problem here.  If the root crown is not entirely destroyed or removed then the kudzu vines can make an extraordinary reappearance the following year, as if from nowhere. So, if mechanical removal is the order of the day, then the fidgety work of ensuring the entire root crown material is removed is an (almost impossible) imperative.

Image Credit Flickr User Cisc1970
Other methods have been considered and are in use.  One is to introduce goats where kudzu is rampant.  Farmers get the benefit of the milk, wool and meat – and also some of their land back.  Constant grazing of kudzu will eventually kill off the plant as it will deplete the carbohydrate reserves in the root crown, so destroying the plant.  However, once the benefits of large scale goat rearing are discovered they are not easily let go of and most farmers will remove their goats to other areas before the plant dies, allowing the kudzu to replenish itself.

Image Credit Flickr User Suzie T
The ability of kudzu to resurrect itself has led to some commentary.

Image Credit Flickr User dview.us
Other products can be made from kudzu, such as baskets, paper and a variety of culinary treats not to mention the fact it can be turned in to kudzu hay and used as a feed for other less athletic livestock.  Yet this hardly makes a dint in the spread of the vine which now covers 7 million acres of the Southeastern United States.  Its spread, it seems, is inexorable.

Image Credit Flickr User lotopspin
Yet, it is said that out of every evil some good must come.  Taking their cue from the way that kudzu has been used in Asian medicine for thousands of years, American chemists have extracted a drug from kudzu root.  Although it has not yet been tested on humans it is hoped that the drug will be useful in the treatment of alcoholism. 

Image Credit Flickr User beardnb
Whether kudzu is regarded as a pest or a miracle cure in the future is down to science.  While we have to wait to see its medicinal benefits it is unlikely that any reputational rehabilitation will discourage those who wish to see this alien vine eradicated.  This story is not yet over.

Image Credit Flickr User softcorestudios
First Image Credit Flickr User gbein83