Plant of the Week 20.03.17

Every week in the office, one of our Apprentices chooses an interesting plant to tell us about.

This week’s Plant of the Week, comes courtesy of Francis, one of our Landscape Gardening Apprentices.

Kudzu is a perennial vine native to Asia, primarily subtropical and temperate regions of China, Japan, and Korea. Five species in the genus Pueraria (P. montana, P. lobata, P. edulis, P. phaseoloides and P. thomsoni) are closely related and kudzu populations in the United States seem to be hybrids of more than one species.

Although kudzu prefers direct sunlight, the plant can survive in partial shade. These attributes made it attractive as an ornamental plant, but kudzu became a “structural parasite” of the Southern US, enveloping entire structures, growing rapidly over trees and shrubs killing them with heavy shading.

It has been spreading in the southern U.S. at the rate of 610 km2 annually, easily outpacing the use of herbicide spraying and mowing, as well increasing the costs of these controls by $6 million annually. This destructive habit has earned Kudzu the name “the vine that ate the south”.

Kudzu spreads by vegetative reproduction via stolons that root at the nodes to form new plants and by rhizomes. Kudzu will also spread by seeds, which are contained in pods and mature in the autumn. One or two viable seeds are produced per cluster of pods. The hard-coated seeds can remain viable for several years, and will successfully germinate only when soil is persistently soggy for five to seven days, with temperatures above 20 °C. Once germinated, saplings must be kept in a well-drained medium that retains high moisture. During this stage of growth, it is critical for kudzu to receive as much sunlight as possible. Kudzu saplings are sensitive to mechanical disturbance, and are damaged by chemical fertilizers. They do not tolerate long periods of shade, or high water tables.