Kudzu

Kudzu, also called Japanese arrowroot is a group of plants in the genus Pueraria, in the pea family Fabaceae, subfamily Faboideae. They are climbing, coiling, and trailing perennial vines native to much of eastern Asia, southeast Asia, and some Pacific Islands. 


The name comes from the Japanese name for the plants, kuzu, which was written "kudzu" in historical romanizations. Where these plants are naturalized, they can be invasive and are considered noxious weeds. The plant climbs over trees or shrubs and grows so rapidly that it kills them by heavy shading. Kudzu is an extremely invasive plant in many asian countries, including Hong Kong.

Reproduction:Kudzu spreads by vegetative reproduction via stolons (runners) that root at the nodes to form new plants and by rhizomes. Kudzu will also spread by seeds, which are formed in pods and mature in the autumn. Three to five seeds are formed in each pod. The hard-coated seeds may not germinate for several years, which can result in the reappearance of the species years after it was thought eradicated at a site.

Major Uses:

Soil improvement and preservation

Kudzu has been used as a form of erosion control and also to enhance the soil. As a fast growing legume, it increases the nitrogen in the soil via a symbiotic relationship with nitrogen-fixing bacteria.Its deep taproots also transfer valuable minerals from the subsoil to the topsoil, thereby improving the topsoil. In the deforested section of the central Amazon Basin in Brazil, it has been used for improving the soil pore-space in clay latosols, thus freeing even more water for plants than in the soil prior to deforestation.


Animal feed

Kudzu can be used by grazing animals, as it is high in quality as a forage and palatable to livestock. It can be grazed until frost and even slightly after. Kudzu had been used in the southern United States specifically to feed goats on land that had limited resources. 

Kudzu hay typically has a 15–18% crude protein content and over 60% total digestible nutrient value. The quality of the leaves decreases, however, as vine content increases relative to the leaf content. Kudzu also has low forage yields despite its rate of growth, yielding around two to four tons of dry matter per acre annually. It is also difficult to bale due to its vining growth and its slowness in shedding water. This makes it necessary to place kudzu hay under sheltered protection after being baled. Kudzu is readily consumed by all types of grazing animals, yet frequent grazing over three to four years can ruin stands. Thus, kudzu only serves well as a grazing crop on a temporary basis.

Invasive species
Ecological damage and roles

Kudzu's environmental and ecological damage results from acting through "interference competition," meaning it out-competes other species for a resource. Kudzu competes with native flora for light, and acts to block their access to this vital resource by growing over them and shading them with their leaves. Plants may then die as a result, from being suffocated.

Control
Crown removal
For successful long-term control of kudzu, it is not necessary to destroy the entire root system, which can be extremely large and deep. It is only necessary to use some method to kill or remove the kudzu root crown and all rooting runners. The root crown is a fibrous knob of tissue that sits on top of the root (rhizome). Crowns form from multiple vine nodes that root to the ground, and range from pea- to basketball-size. The older the crowns, the deeper they tend to be found in the ground, because the root grows deeper with age. Nodes and crowns are the source of all kudzu vines, and roots cannot produce vines. If any portion of a root crown remains after attempted removal, the kudzu plant may grow back.


Mechanical methods of control involve cutting off crowns from roots, usually just below ground level. This immediately kills the plant. Cutting off vines is not sufficient for an immediate kill. It is necessary to destroy all removed crown material. Buried crowns can regenerate into healthy kudzu. Transporting crowns in soil removed from a kudzu infestation is one common way that kudzu "miraculously" spreads and shows up in unexpected locations.