Perilla frutescens
(Beefsteak Plant, Perilla, Purple Basil)
Where it originates:
Perilla frutescens is an annual herb native to China, Japan, India, Korea, and other Asian countries. It was introduced in North America as an ornamental, and as a cultivated plant used in salads, cooking, and even considered a substitute for basil in cases.
Identification:
Typically has green leaves with purple tinge, which are arranged oppositely with distinctly toothed margins. Leaves are oval shaped and emit a minty odor when crushed. P. frutescens may only reach groundcover height along shaded roadsides, while growing more than three feet in sunny, rich soil. Flowers emerge from late July to October occurring in terminal clusters, or “spikes.” Spikes appear hairy, flowers are small and white to purplish along clusters.
Habitat:
Disturbed areas including; roadsides, trails, fields, pastures, and fencerows. P. frutescens has invaded nearly every state in the eastern U.S., as far west as Texas.
Ecological Impacts:
P. frutescens has very few predators due to toxic characteristics. Like other members of the mint family, chemicals within the plant repel insects, and will typically repel mammals that might consume it. P. frutescens is especially toxic to cattle and sheep, and can be a serious concern where the plants invade hayfields. In forested areas P. frutescens outcompetes natives by shading them out and preventing native regrowth in disturbed areas. Its windborne seeds are dispersed very easily, and will readily reseed each year. Without control measures P. frutescens can form dense monocultures that displace native groundcover and provide no benefit to most wildlife.
Control:
Chemicals with a gyphosate base such as Round Up can effectively control P. frutescens, however herbicide must be applied before seeds are produced in the fall. Always follow directions on your herbicide label, and be well aware and cautious of nearby waterways when applying.
Hand pulling will also work well to control P. frutescens. After the plant has flowered this is the best option for control. Always be sure to remove as much of the plant as possible, and compost or burn before disposing in a landfill. Simply bagging and throwing away may actually lead to the spread of the plants seeds.
All control methods must be minimally repeated on a yearly basis to reduce populations and gain control of spread.