Photographer: Robert J. Richardson Affiliation: North Carolina State University Source: Bugwood.org Copyright: (CC BY-NC 3.0)
Bushkiller (Cayratia japonica) is a perennial vine, with compound leaves, and five smaller leaflets on each leaf. The leaflets or orbicular, 1-3 in long, 0.5-1.5 inches wide. Small, pale pink flowers develop in umbrells on the plant during the summer months of June to August. Small, dark colored fruits appear in late summer on the flowers with two or three seeds per fruit.
Bushkiller is known for its rapid growth rate and ability to grow in thick dense mats while attached to other vegetation, preventing light from reaching the host plant. If bushkiller is allowed to grow freely on shrubs or trees it will eventually kill the host due to lack of necessary sunlight for photosynthesis. Forests and fields are both at risk for damage from bushkiller because it is able to grow in both habitats and attach easily to many host plants.
It is believed that bushkiller will only reproduce vegetatively in the United States. Sprouting from roots occurs producing spores, which allow for propagation of bushkiller.
The exact method of introduction of bushkiller is unknown, and the plant is not currently regulated in the United States. With the damage threat to U.S. forests, there is interest in placing regulations on distribution and propagation of the plant.
Habitat: Bushkiller is found in a variety of habitats that have been somewhat disturbed, allowing for introduction and initial propogation of the plant. Harvested forests, cultivated fields, and residential areas are the most common places that bushkiller is observed.
U.S. Present: HI, LA, MS, NC, TX
Management tips for bushkiller are rather bleak with no known biological or chemical controls. Mechanical management of the plant is the only viable option and requires extensive labor to prevent the plant from regenerating and attaching to new host plants. If manual pulling of the plant is utilized it is important to remove the entire plant including the root system because it is capable of regenerating from roots alone.
Maddox, Victor, John D. Byrd Jr., and Randy Westbrooks. 2007. Bushkiller. Wildlands (Pamphlet).
West, Amanda M. 2009. Biology and Management of Bushkiller (Cayratia japonica). North Carolina State Masters Thesis.
West, Amanda M., Robert J. Richardson, Consuelo Arellano, and Michael G. Burton. 2010. Bushkiller (Cayratia japonica) growth in interspecific and intraspecific competition. Weed Science 58(3):195-198.