Kudzu (Pueraria montana)
Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.
Deciduous twining, trailing, deep mat-forming, ropelike woody leguminous vine, 35 to 100 feet (10 to 30 m) long with 3-leaflet leaves. Large semiwoody tuberous roots reaching depths of 3 to 16 feet (1 to 5 m) with a knot- or ball-like root crown on top at the soil surface where vines originate. Leaves and small vines dying with first frost and matted dead leaves persistent during winter.
Woody vines to 10 inches (25 cm) in diameter, round in cross section, with infrequent branching. Stems succulent and yellow green with dense, erect golden hairs and upward-matted silver hairs, aging to ropelike and light gray barked. Frequent unswollen nodes root when on the ground to form new plants when interconnecting vines die, eventually growing large with age to form root crowns 1 to 10 inches (2.5 to 25 cm) wide. Mature bark eventually rough, rigid, and usually dark brown.
Alternate, pinnately compound 3-leaflet leaves, each leaflet 3 to 7 inches (8 to 18 cm) long and 2.5 to 8 inches (6 to 20 cm) wide. Usually slightly lobed (unless in shade) with a 2-lobed symmetric middle leaflet and two 1-lobed side leaflets. Tips pointed. Margins thin membranous and fine golden hairy. Leaflet stems (petiolules) swollen near leaftlets. Petrioles 6 to 12 inches (15 to 30 cm) long, long hairy, base swollen, with deciduous stipules.
June to September. Axillary slender clusters (racemes), 2 to 12 inches (5 to 30 cm) long, of pealike flowers in pairs (or threes) from raised nodes spiraling up the stalk, opening from the base to top. Petals lavender to wine colored with yellow centers. Fragrant, often reported with the scent of grapes.
Fruit and seeds
September to January. Clustered dry, flattened legume pods (bulging above the seeds) each 1.2 to 3 inches (3 to 8 cm) long and 0.3 to 0.5 inch (8 to 12 mm) wide. Green ripening to tan with stiff golden-brown hairs. Falling whole or splitting on 1 to 2 sides to release a few ovoid seeds.
Can grow 1 foot (30 cm) per day in spring and 60 feet (18 m) per year. Occurs in old infestations, along right-of-ways, forest edges, and stream banks. Forms dense mats over the ground, debris, shrubs, and mature trees forming dense patches by twining on objects less than 4 inches (10 cm) in diameter. Colonizes by vines rooting at nodes and spreads by wind-, animal-, and water-dispersed seeds. Seed viability variable by habitat and across the region. Leguminous nitrogen fixer.
History and use
Introduced from Japan and China in early 1900s with continued seed importation. Limited use for erosion control, livestock feed, and folk art.
Found throughout the region with scattered dense infestations in every State. Especially frequent in MS, AL, GA, and northwest SC.
- Do not plant. Remove prior plantings, and control sprouts and seedlings. Bag and dispose of plants and seed pods in a dumpster or burn.
- Treat when new plants are young to prevent spread.
- Anticipate wider occupation when plants are present before disturbance.
- Root crowns can be removed with mattocks, hoes, and saws, while removal of the tuberous taproot is not required for control.
- Mow and then cover for 2 years with plastic sheeting firmly fastened down to gain partial control.
- Repeated multiyear cutting to groundline can achieve control over many years.
- Prescribed burning in spring can clear debris, sever climbing vines, and reveal hazards before summer applications.
- Repeated burns will not control. Burns are hot especially in winter.
- Tender new shoots are readily eaten by cattle, hogs, and horses, while only goats and sheep will eat semiwoody and woody vines. Prescribed grazing can reduce infestations over several years while pine tree planting in latter years can yield a fully stocked plantation with minimal kudzu.
Recommended control procedures
- Thoroughly wet all leaves, including those on climbing vines, as high as possible with one of the following herbicides in water with a surfactant: (June to October for successive years when regrowth appears) Tordon 101* ‡ as a 3-percent solution (12 ounces per 3-gallon mix) or Tordon K* ‡ as a 2-percent solution (8 ounces per 3-gallon mix), either by broadcast or spot spray; (July to early September for successive years) Escort XP* at 3 to 4 ounces per acre (0.8 to 1.2 dry ounces per 3-gallon mix) or Milestone VM* at 7 ounces per acre (2 ounces per 3-gallon mix) in water. When safety to surrounding vegetation is desired, use Transline* † as a 0.5-percent solution in water (2 ounces per 3-gallon mix) or Milestone VM* can safely treat kudzu under many desirable trees and shrubs if herbicide is not applied directly to them.
- For partial control and no soil activity, repeatedly apply Garlon 4 or a glyphosate herbicide as a 4-percent solution in water (1 pint per 3-gallon mix) with a surfactant during the growing season. Or cut large vines and immediately apply the herbicides to the cut surfaces or apply the ready-to-use Pathway* or ORTHO Brush-B-Gon, Enforcer Brush Killer, and Vine-X readily available in retail garden stores (safe to surrounding plants). ORTHO Brush-B-Gon, Enforcer Brush and other "poison ivy" herbicides can be used as foliar sprays.
- To control vines less than 2 inches in diameter, apply basal sprays of Garlon 4 as a 20-percent solution (5 pints per 3-gallon mix) in a labeled basal oil product, vegetable oil, kerosene, or diesel fuel (where permitted) (January to April); or use undiluted Pathfinder II.
- For larger vines, make stem injections using Tordon 101* ‡, Stalker*, Arsenal AC*, or a glyphosate herbicide using dilutions and cut-spacings specified on the herbicide label (anytime except March and April).
* Nontarget plants may be killed or injured by root uptake.
‡ When using Tordon herbicides, rainfall must occur within 6 days after application for needed soil activation. Tordon herbicides are restricted use pesticides.
† Transline controls a narrow spectrum of plant species.