What is Kudzu? And What Can We Do About It?

What is Kudzu? And What Can We Do About It?

By Michael Jenkins

Let us start by saying this: at Gardzen we believe there are no bad plants, just plants that may be in the wrong place. Invasives are such plants—they’re perfect in their native spaces but become a problem when introduced elsewhere. Kudzu is one such plant. A native used as an ornamental or ground cover in its natural environment, it became a highly invasive weed in other parts of the world. But what is kudzu, really? What can we do about it? Do we need to take steps to eliminate kudzu from our spaces, or should we let it be? Let’s dig in and learn a bit more about this plant and about invasives in general.

The Origins of Kudzu

Where does kudzu come from? If you live in North America, you may associate the plant with the southeastern part of the country, but the reality is that kudzu has its origins elsewhere. Ultimately this plant is from Asia—most likely Japan, where it is known by the name “kuzu” or “クズ/葛”. The population in the United States is descended from four or five closely related species from the Fabaceae family, meaning that they’re related to peas. Kudzu is primarily derived from Pueraria montana, although some other Pueraria species have contributed to its genetic makeup in the US.

So how did kudzu make it from Japan to the United States, Europe, and other places? Kudzu made its first international appearance as part of the Japanese display at the 1876 Central Exposition in Philadelphia, PA. It became a popular ornamental and garden plant, as its colorful blooms made it a engaging alternative to ivy and other climbing or groundcover plants. Kudzu became popular around the world as an agricultural plant during the Great Depression, when it was marketed as a soil rejuvenator and a means to prevent erosion.

We should all remember that kudzu is a very useful plant. As a Fabaceae, kudzu acts as a nitrogen fixer and helps enrich the soil. Its rapid growth and ability to root anywhere helps prevent soil erosion. Pollinators love the flowers, and the leaves are nutritious for both animals and humans (NOTE: please don’t eat kudzu you find in the wild. It has very often been sprayed with pesticides and can cause serious health issues.) In the Appalachian mountains, kudzu vine is used to weave baskets and woven fencing. We’re told the plant also has traditional medicinal uses. The point in this is that kudzu is not a bad plant at all, just a plant moved to the wrong place.

Why is Kudzu so Invasive?

So why is kudzu such a problem in so many places? Across most of the US and Canada, much of Europe, New Zealand, Australia, and the South Pacific it is classed as an invasive, a noxious weed, or an undesirable organism. It is illegal to plant, transplant, or even to possess the seeds in many places. How could such a useful plant be undesirable?

The answer comes from its growth cycle. In the more temperate climate of Japan and its neighbors of Korea and northern China, kudzu grows rapidly during the warmer months but dies off when the cold winters arrive. In climates with milder winters—famously the southeastern US—kudzu just keeps growing and growing, and that’s when it becomes a problem. In some places kudzu overgrows and kills trees, crowds out native plants, and even damages buildings. As it propigates from both seeds and underground rhizomes, it’s extremely difficult to eliminate unless caught very early. In the southeastern US, kudzu became so prolific that it is referred to as “the plant that ate the South” and with good reason.

Removing and Eliminating Kudzu

So what can you do if you have kudzu on or near your property? The first step may be to inform your state or province department of natural resources, department of agriculture, or department of environmental quality. Many states, provinces, and municipalities like to track kudzu growths as part of the containment process and may send experts out to assess the situation.

Eliminating or removing kudzu once it is established is a daunting task. The best method seems to be regular and aggressive mowing combined with digging out the root crown and the main roots. Done regularly, this can turn the tide and gradually eliminate kudzu from your property. If the kudzu is unsprayed and your circumstances permit you to do so safely, you can turn goats, llamas, cows, or other livestock loose in the area and let them help eliminate it naturally while fertilizing your soil as well. Many cities or affected areas have livestock rental services for this purpose.

Herbicides may work for kudzu, but we feel that measure is best left to the experts. Applying herbicides is a last resort measure, and when applied widely and over a long duration we feel that a qualified technician should administer them. Killing kudzu with herbicide can be a ten year process, so let the folks who know how take care of it.

Kudzu’s History and Future

Across the southeastern US in particular, there is a renewed interest in cultivating kudzu under controlled conditions as animal feed, a carbon capture plant, and even for bio-fuels. This is fitting with its history as a useful and helpful plant when grown correctly, and it will be interesting to see how things develop along those lines. Until then, we gardeners just need to do our best to live with and around this plant and keep it from overwhelming spaces to which is isn’t native and in which it could be harmful.

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