kudzu

Pueraria montana var. lobata
Vine
Alternate
Compound
Purple
Blue
Green
Discoloured

A large twining or creeping vine with relatively thick stems covered with long yellowish-brown hairs. Its thickened roots develop into large tubers (up to 1.8 m long and 15 cm wide). Its very large alternately arranged leaves have three lobed or un-lobed leaflets (7-20 cm long and 5-13 cm wide). Its pea-shaped flowers (12-20 mm long) are arranged in elongated clusters in the leaf forks. These flowers are; purple, blue, pink or violet in colour with a yellow spot near their centres. Its fruit is an elongated and flattened pod (5-12 cm long) that is densely covered in rusty-coloured hairs.

Common names 
Also known as: kudzu, Japanese arrowroot, kudzu vine,
Family 
Fabaceae
Deciduous 
No
Flowering time 
Summer
Native/Exotic 
Exotic
Origin 
Native to temperate north-eastern Asia and tropical south-eastern Asia. Probably also native to, or an early introduction to, some western Pacific islands. It is also present in the coastal districts of north-eastern Northern Territory, and is regarded as
Notifiable 
Yes
State declaration 
Class 2
Council declaration 
Class E - Early detection and eradication
Known distribution 

Kudzu (Pueraria montana var. lobata) is scattered in the coastal districts of eastern Australia. It is naturalised in northern, central and south-eastern Queensland and in the coastal districts of northern and central New South Wales. It is also naturalised on Norfolk Island. Naturalised overseas in the USA, Mexico, Central America (i.e. Panama), eastern Europe (i.e. Ukraine), western and central Asia, southern Africa and on some Pacific islands (i.e. Hawaii, American Samoa, Western Samoa, French Polynesia and Tonga).

Habitat 

A weed of riparian vegetation, moist forests, watercourses, roadsides, waste areas and disturbed sites in warmer temperate, sub-tropical and tropical regions.

Habit 

A large twining or creeping long-lived (i.e. perennial) vine with stems up to 10 m long which can quickly envelope trees or spread rapidly across the ground. Its thickened roots develop into large tubers (up to 1.8 m long and 15 cm wide).

Impact and control methods 

Kudzu (Pueraria montana var. lobata) is regarded as an environmental weed in Queensland and New South Wales. It is also listed as a priority environmental weed in at least one Natural Resource Management region.

Stem and leaves 

Its rampant stems are relatively thick and covered with long, appressed to spreading, yellowish-brown hairs. The very large alternately arranged leaves are compound with three leaflets (i.e. they are trifoliate) and borne on stalks (i.e. petioles) 8-13 cm long. At the base of each leaf stalk there is a pair of small leafy structures (i.e. stipules) 8-16 mm long. Each of the large leaflets (7-20 cm long and 5-13 cm wide) may be un-lobed or slightly lobed and usually has pointed tips (i.e. acuminate apices). The uppermost (i.e. terminal) leaflet is usually slightly larger and three-lobed, while the two side (i.e. lateral) leaflets usually have two lobes. Some or all of these leaves may be shed during cooler and/or drier conditions (i.e. it is deciduous). Both sides of the leaflets are sparsely hairy (i.e. pubescent). The upper surfaces are light green while the undersides are grayish-green.

Flowers and fruits 

The pea-shaped flowers are produced during summer and are borne in elongated clusters (15-40 cm long) in the upper leaf forks (i.e. in axillary racemes). These clusters contain up to 90 purple, blue, pink or violet-coloured flowers (12-20 mm long). The flowers have five sepals (6-12 mm long), that are fused together at the base, and five petals. The uppermost petal (i.e. standard) is larger that the two side petals (i.e. wings) and has a yellow spot near its base. The two lower petals are fused together and folded (i.e. into a keel). The flowers also have ten stamens, nine of which are fused together with the other being separate from the rest, and an ovary topped with a style and stigma. The fruit is an elongated and flattened pod (5-12 cm long and about 12 mm wide) that is densely covered in rusty spreading hairs. These pods contains several (8-12) seeds.

Reproduction and dispersal 

Kudzu (Pueraria montana var. lobata) reproduces mainly vegetatively by runners (i.e. stolons) and creeping underground stems (i.e. rhizomes). It occasionally also reproduces by seed.The seeds can be dispersed in water and contaminated soil, while the stem segments and rhizomes can be spread in dumped garden waste and contaminated soil.

Similar species 

Kudzu (Pueraria montana var. lobata) is very similar to tropical kudzu (Pueraria phaseoloides), but these two species can be differentiated fron each other by the following differences: kudzu (Pueraria montana var. lobata) produces large underground tubers up to 1.8 m long and 15 cm wide and its fruit are relatively wide (about 12 mm across). tropical kudzu (Pueraria phaseoloides) does not produce any underground tubers and its fruit are relatively narrow (about 5 mm across).