America Spends Millions Fighting This Plant. Korean Kids Used to Dig It Up for a Snack.Pueraria montana var. lobata · 칡

 America Spends Millions Fighting This Plant. Korean Kids Used to Dig It Up for a Snack.

Pueraria montana var. lobata · 칡

When I was young, finding a good 칡 root was a skill. You learned it from older kids or from adults who had grown up doing the same thing — following the vines back from wherever they were climbing, tracing the stems down to the ground, digging at the base until the root came loose. Some roots were sweet and worth chewing. Others were bitter all the way through and you spat them out. The ones worth keeping had a clean starchiness to them, a faint sweetness under the earthiness, and you chewed them slowly, working the starch out of the fiber the way a cow works cud, until there was nothing left but dry threads you threw away.

This was a snack. There were no convenience stores. There was a river bank, a hillside, and whatever grew there.

That plant — the one Korean children dug up and chewed on summer afternoons — is the same plant that American states have been trying to eradicate for decades. The same vine that covers entire hillsides in the photographs above is, in the American South, classified as a federal noxious weed and described in news articles as "the vine that ate the South." The United States spends an estimated $500 million annually managing kudzu infestations across the southeastern states, where it smothers forests, collapses structures, and has been spreading at a rate that briefly panicked ecologists in the late twentieth century.

In Korea, it just grows on the riverbank. Children dig up the roots.

 What It Is

Pueraria montana var. lobata belongs to the Fabaceae — the legume family — and is native to eastern Asia: China, Korea, and Japan primarily. In East Asia, kudzu has been cultivated for over 2,000 years as a forage crop, a fiber source, and a medicinal plant. The starch extracted from the thick roots was used in cooking — kudzu starch (칡전분) thickens sauces and soups the way arrowroot or cornstarch does, and was a significant food source in lean times.

It can cover trees up to thirty meters tall and can grow up to 30 cm per day under ideal conditions — which is fast enough to be visible if you watch it for long enough, and fast enough to explain how it covers entire hillsides by midsummer. The stems are woody at the base, the leaves large and trifoliate with three broad leaflets covered in fine soft hairs. When the plant climbs, it twines and scrambles rather than gripping — it uses its own weight and the density of its growth to stay in place.

The flowers — which are what these photographs captured — are not commonly seen, because they open among the dense foliage and are easy to miss. They are small, intensely purple-red, with the typical legume structure: a broad upper petal (the standard), two lateral wing petals, and a central keel enclosing the reproductive structures. Up close they have a faint grape-like fragrance. Most people who have lived near 칡 their entire lives have never seen the flowers.

 The Two Medicines Inside One Plant

Traditional Korean and Chinese medicine distinguished carefully between two different parts of the 칡 plant, and for good reason — they have different properties.

The root, dried, is 갈근 (葛根) — one of the most important herbs in East Asian pharmacopoeia. It appears in classical medical texts including the Dongui Bogam and has been prescribed for fever, neck stiffness, headache, diarrhea, and thirst. Kudzu root contains isoflavones that exhibit estrogen-like effects and possess anti-inflammatory and neuroprotective properties. Modern research has investigated puerarin — the primary isoflavone in the root — for cardiovascular effects, blood sugar regulation, and neuroprotection.

The flower, dried, is 갈화 (葛花) — and this is where the hangover remedy tradition actually comes from. Research has confirmed that the flower enhances acetaldehyde removal from the body, which is the mechanism behind hangover relief. The distinction matters because the root and the flower have different traditional claims and constituents. *Pueraria flos* (the flower), which enhances acetaldehyde removal, is the traditional hangover remedy. Various commercial hangover products in Korea contain 갈화 extract, and the traditional use is pharmacologically coherent.

The root has a more complicated relationship with alcohol — Pueraria lobata (the root) is a known inhibitor of mitochondrial aldehyde dehydrogenase and is being investigated for use as an aversion therapy for alcoholics  rather than a hangover cure. The two parts of the same plant work in opposite directions with respect to alcohol metabolism — a distinction that traditional Korean medicine recognized long before modern pharmacology confirmed it.

 The American Disaster

Kudzu was introduced to the United States in the 19th century, initially for erosion control and as forage for animals. However, it quickly became an aggressive invader, especially in the southeastern U.S., earning its reputation as "the vine that ate the South."

The US Department of Agriculture actively promoted kudzu planting in the 1930s and 1940s as a solution to soil erosion in the Depression-era South, paying farmers to plant it. By the 1950s, the scale of the problem was becoming clear. By 1970, kudzu was classified as a weed. By 1997, it was listed as a federal noxious weed. The vine now covers an estimated 3 million acres across the southeastern United States and continues spreading northward as winters warm.

The reason kudzu behaves so differently in the American South than in Korea is ecological. In Korea, 칡 grows alongside the insects, fungi, soil bacteria, and competing plant species that evolved with it and keep it in check. In the American South, it arrived without any of those constraints and found a climate almost perfectly suited to its growth habits. The same plant, different continent, no biological brakes.

 How to Identify It

칡 in summer is one of the easier vines to identify once you know the leaf pattern. The leaves are trifoliate — three leaflets per leaf — with each leaflet broadly oval and sometimes shallowly lobed, covered in soft hairs that give the surface a slightly dull rather than glossy appearance. The leaflets are large, typically 7–15 cm long, and the whole leaf has a slightly drooping quality in still air.

The stems twine counterclockwise up whatever support is available — fences, walls, shrubs, trees — and the older stems at the base of established plants become woody and rope-like, sometimes reaching the thickness of a wrist on plants that have been growing for years.

The flowers, when they appear in July and August, are in tight upright racemes of deep purple-red blooms with a characteristic grape-like fragrance. Finding them requires looking into the mass of foliage — they don't hang out where you can easily see them from a path. After flowering, the plant produces flat, hairy seed pods in the typical legume pattern.

The root, underground, can reach extraordinary sizes on older plants — thick, starchy, and deeply anchored. This is what Korean children dug up. This is also what makes eradication so difficult in the United States: cutting the vines at the surface does nothing if the root remains.

I don't see children digging up 칡 roots anymore. The plant is still there — if anything, more of it than there was — but the impulse to treat a riverbank vine as a food source has largely passed out of living practice. The knowledge of which roots are sweet and which are bitter, which the adults once had, is not being passed down in the same way.

The Americans would find this baffling. They see a plant that costs millions to fight and produces nothing worth having. The older Koreans who grew up on riverbanks knew something different: that what looks like a weed from one angle looks like a starch-filled snack from another, depending entirely on what you already know about it.

 Disclaimer: This post is for educational and informational purposes only. While 칡 (Pueraria montana var. lobata) has a long history of food and medicinal use in Korea, the root and flower have different pharmacological properties and should not be self-administered medicinally without consulting a qualified healthcare professional. People with hormone-sensitive conditions, those taking medications, or those with liver conditions should exercise particular caution. Do not harvest plants from areas that may have been treated with herbicides. The author is not a licensed botanist or medical professional. Nothing in this post constitutes medical advice.