Stat Counter

Friday, September 14, 2012

Kudzu, the miracle plant that ate the South

If you are like me you have heard horror stories and seen disturbing pictures of kudzu.  Huge swaths of forest decimated by this one plant, street signs overran by climbing vines.  Even cars surrounded by the clinging tendrils of this green monster.  It has become the poster child for the dangers of invasive species.  That is why the book of Kudzu surprised me so much.  It taught me that there is much more to this plant than simply an ornamental that got out of control.
Kudzu is originally from Asia and is used there for the starch in its roots.  Here the starch is often sold as arrowroot.  It is a pure white powder, similar to cornstarch, and with many of the same properties.  It can be used to cook with, and especially can be used as a thickening agent.  Kudzu starch likely has the same industrial applications as corn or potato starch do.  But Kudzu is a legume, and improves the soil that it grows on, unlike either corn or potatoes. 
Kudzu is also a source of forage.  I was always under the impression that it was an ornamental that escaped into the wild and took over.  It wasn't.  Kudzu was used for erosion control throughout the south, often on steep embankments that nothing else would live on.  However, it was originally championed by farmers for its leaves, providing large amounts of forage in very little time, even on marginal land.  The original promoters of Kudzu saw it as a way to use corn, wheat, and soybeans for human use, while improving land and providing forage through the use of kudzu. 
In the South, there were a number of factors for why Kudzu erupted like it did.  One is that Kudzu has a phenomenal growth rate.  One joke says that when you plant kudzu, you should drop the seed and run so you don't get caught by it.  Another factor is that there are few if any natural controls of Kudzu. In its native land, there are numerous insects and animals that have evolved around kudzu, and thus limit its growth.  Another factor is that in Asia where kudzu is native, the climate is relatively cool and wet.  The warm wet seasons provide a boost to kudzu growth.  And lastly, in its native region, kudzu is harvested and used.  In the Southern U.S. there is little use of kudzu, so the vines have no checks to their growth.
Kudzu could be a major crop however.  In addition to the starch content of the roots, and the forage value of the leaves, the stems could be useful as well.  Kudzu stems are woody and are not palatable to farm animals.  However, they could be used for things like baskets, and could likely be a cheap source of cellulose for paper production.  In addition, the stems are fibrous, and like hemp or flax, can be used to produce cloth given the right conditions.  Granted it takes nearly 50 pounds of stems to produce 1 lb of cloth, but rampant growth of kudzu makes 50 lbs of stems relatively easy to collect. 
One of the main advantages of Kudzu is that it is a legume.  Legumes fix nitrogen from the atmosphere and help to improved the soil as they grow on it.  Few legumes offer the multitude of uses that Kudzu does, and few grow as well in a variety of conditions.  There was one case of Kudzu being used as a green manure, where 10 years after the kudzu was grown there was still a difference in yield between the test plot and the control.  If it could provide that much of a help with little or no input, Kudzu would be a boon to organic farmers.
Now I am not advocating that Kudzu be used in areas where it could take over like it did in much of the South.  However, there are conditions that would limit kudzu's growth and make it easier to control.  First would be relatively dry conditions.  Because of its large taproot, kudzu can easily withstand long periods of drought.  It does however need around 20 inches of rain per year or it would have to be irrigated.  It grows best in conditions of up to 40 inches of rain per year, and so the semi-dry areas of the country would be more likely to grow it in controlled situations.  In addition, Kudzu likes warm summers and mild winters.  Places with harsh dry winters have a much easier time to control the kudzu as it is dormant for longer periods.  Through the Midwest it seems kudzu could be used with less of a chance of it dominating the landscape as it does in portions of the South.
Overall, it seems that kudzu mostly has a bad reputation because people were unused to it and didn't know how to use it.  Perhaps if it was grown in areas where it would be limited, kudzu could become a beneficial crop.  And before you start to make the case that kudzu is a non-native species, remember that most of our farm animals and farm crops are also non-natives. 

The Book of Kudzu by William Shurtleff and Akiko Aoyagi can be found here to read online.

Live a Hands-on life

No comments:

Post a Comment