Oigawa Kudzu-fu Weaving Studio

What's Kudzu?

what's kudzu


kudzu flower

Kudzu, a fast-growing and versatile plant, is a member of the legume family that can be found all over Japan.
Its roots are used to make kudzu flour, a staple ingredient in many Japanese dishes, while the dried roots are used in herbal medicine to reduce fever.
Kudzu flowers bloom in early autumn and are a stunning magenta color, resembling wisteria flowers, with a sweet scent.
Its leaves are a great source of starch and make a delicious treat for livestock, which is why it is often called "pig vine" or "horse cake" in some areas.
Kudzu vines are also used for making baskets, and even vine bridges.
Kudzu, also known as the "Vine Ate the South" in the United States, is a plant that can grow up to 30 meters in length and is considered one of the fastest-growing plants in the world. 
It belongs to the legume family and has sheaths.
Despite its reputation as a pest plant in some regions, kudzu has clever strategies for propagation. Its vines can grow roots from vine sections or produce seeds after flowering. Its seeds can remain dormant for years, waiting for the right conditions to germinate. 
Kudzu is also known for its unique features, such as its ability to cling to other trees without needing to form xylem, which helps it save energy for rapid growth.
In Japan, kudzu is a valuable plant used for a variety of purposes, from food and medicine to crafting.

Kudzu, described in the botanical encyclopedia written by Tomitaro Makino, is scientifically known as Pueraria thunbergiana Benth. It usually grows in mountains and wild fields, and its vine spreads widely. Kudzu has a perennial coiling vine, and the core of the vine becomes wood. It has brown rough hair covering its surface and can coil up to a length of more than 10 meters.
The leaves of kudzu grow thick and alternate, and they are green in color with rough hair sparsely covering them. The back of the leaves can be seen with whitish color and bristly white hair. In autumn, it stands bunch flower 15-18cm in length and blooms purple butterfly-shaped flowers. The flower blooms sequentially from the bottom, and it has a length of 18-20mm. The calyx has a pale purple color. The flower turns into a fruit that has a linear shape and a length of 5-10cm. It is covered with rough brown hair.
Kudzu's roots grow very big and are useful for medicine. Starch can also be obtained from these roots, and the leaves are useful for feeding cattle. The Japanese name for kudzu is an omission of "kudzukazura" in Japanese. There is an area named "Kudzu" in Nara prefecture, where in ancient times, people lived and peddled kuzu starch. That's why that area was called Kudzu.
「Makino shin nihon syokubutsu zukan wrote by Tomitaro Makino Hokuryukan , June 25 1961 p323」

Kudzu in east Asia
◆Pueraria thomaonii   grows in south China , Vietnam and India
◆Pueraria montana     grows in south China Kanton Kansai Fukken and Taiwan


kudzu vines in Ryukyu island

  • There are two species of kudzu: Pueraria lobata and Pueraria montana.

  • When I visited Okinawa Island in October 2005, some Okinawan people brought me a kudzu vine. It was clearly different from the kudzu on Honshu (the main island of Japan). I thought it was Pueraria montana, as it had longer flowers and smaller leaves than Pueraria lobata, which mainly grows on Japan's main island.


Long flower Okinawa island 2005

I walked around North Nakagusuku village in Okinawa in October 2007 and found a small group of Pueraria montana, but I could not find Pueraria lobata. It seemed that the Pueraria montana in Okinawa did not have the same overwhelming fertility as the ones on the main island.


As of now, 300 million hectares of the United States are covered with kudzu vines. This excludes land where the plant grows naturally and the value of the affected land is depreciated. The use of poisonous herbicides to exterminate kudzu as a harmful weed in both the country and the state is being examined. However, the use of herbicides can have negative impacts on the environment. Therefore, I suggest exploring the possibility of utilizing kudzu as a resource.
This is a letter from Beniko Takeda, a former student of North Carolina State University, written in January.

kudzu seeds in winter at
Ooigawa river

■ Vegetative propagation
Kudzu can be propagated both by seed and vegetatively. While kudzu seeds can fall on the ground and grow successfully, the resulting plants don't produce flowers, so there is no seed production. However, vegetative propagation begins at this stage.
When a kudzu vine touches the ground, it is able to extend roots from various sections. If both sides of the section establish roots, it can continue growing as a new independent plant.
■Breeding by seed
Kudzu can be bred through seeds, which are typically planted in the winter. Kudzu seeds are generally easy to germinate, but some seeds have a hard coating which can make germination more difficult. However, the germination rate of kudzu seeds can be low. In order to reduce the risk of relying solely on seed propagation, it may be beneficial to consider diversifying cultivation methods when cultivating new land.
■Leaves movements 
Leaf movements can be adjusted to optimize photosynthesis. For instance, kudzu plants can form dense swarms to avoid excessive water evaporation, which can help to optimize photosynthesis by preserving water resources.
■ Growth form to lose woody parts
Kudzu has a growth form that allows it to lose its woody parts. Unlike plants with hard vines that enable them to support their body vertically, kudzu coils up around other plants and concentrates its leaves at the top of its community. This means that kudzu can use its nutrients for leaves and vines to grow, rather than for vertical support.
Reports indicate that kudzu can extend its vines by 18-50cm per day.
■Benefits of huge roots
Kudzu's roots have such high-level vegetative storage that they are able to thrive in dry lands.