Welcome to the wonderful world of weedy plants!
Weeds are superevolutionary products of human civilizations and activities - without humans there would be no weeds, just wild plants.

Wednesday, November 19, 2014

Kudzu Has Outsmarted Us

Guest post by Patricia Chan, a freshman in 2014 Byrne seminar on weedy plants

Let me tell you about Pueraria montana var. lobata —it is a crazy, crazy, invasive weed.  This plant, commonly known as Kudzu, but also known as Japanese arrowroot, is a plant in the pea family, Fabacaeae.  You may be thinking: “it’s related to the pea, I guess it probably climbs” (ok you probably didn’t think that, but bear with me).  Well if you were thinking that, you are more than right.  Kudzu is an aggressive and skillful climber, much to the dismay of property owners of the southern United States. But before I tell you about this insane plant, let’s discuss how to recognize it in the wild.

File:Kudzu field horz1.JPG

CC Gsmith 

If you happen to stroll around anywhere in the southeast US and encounter a large green mass where there probably shouldn’t be one  - Congratulations!  You have found Kudzu. Kudzu is a very distinguishable plant from afar due to its tendency to cover large areas.   Up close, it may be slightly harder to recognize.  It’s got compound trifoliate leaves (meaning it has three leaflets on one stem) with a varying number of lobes on each leaflet from 1-3 lobes.  The leaves are fuzzy by the way, like a rabbit.  Like a very small, green, coarse, leaf-shaped rabbit…  The long vines cling to surfaces with little brown bristles that it uses to grapple over trees and buildings.  The flowers are a lovely deep pinkish purple hue and grow in clusters.  That’s nice.

photo by Peggy Greb, public domain 

Anyway, now that you know how to point out Kudzu when you see it, let’s learn more about how it behaves.  Kudzu has a very aggressive growing habit; in the right conditions, it can grow up to one foot per vine a day.  Monstrous.  People have reported losing entire cars to masses of Kudzu because they were parked for a few days.  How crazy is that?  In nature, Kudzu is considered a nuisance because it can envelop entire trees in short periods of time, killing forests by crowding out the light.  What a horrible plant to bring places, one may assume.

With that in mind, how did Kudzu even get here, not being native to this continent?  Maybe by a shipping mistake or a tourist?   No, in fact, Kudzu was brought to this country intentionally from Asia for ornamental and erosion prevention purposes.  That’s right, us humans spread this plant ourselves.  The sad truth is that we didn’t do the research we should have to ensure that this plant didn’t damage our ecosystems the way it did.  We just brought it over on a hypothesis and a whim.

This just goes to show: it’s wise not to mess with the natural order of things.  Not to say that it’s impossible to introduce a foreign species successfully, but a lot of heavy research must be done before it happens to make sure a monster isn’t unleashed.  All in all, Kudzu isn’t actually a wholly evil plant.  It carries medicinal purposes, has beautiful flowers, and it really does prevent erosion.  And in the end, it only behaves the way it because these characteristics have helped it to survive and reproduce in the past.  Kudzu acts to survive, and it just so happens that it is really good at doing that in the US.  What we need to do, however, is be more careful to monitor this kind of thing when considering what exotic plants to put where.  We need to be smart in our ecological decisions.

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