Did You Know?
A few facts:
- Can be toxic to livestock
- Can be used for medicinal and culinary purposes
How to get rid of perilla mint:
- Remove manually
- Treat with herbicides
Information by Rakesh Chandran, Ph.D., WVU Extension Service Weed Science Specialist
A Pasture Plant of Concern
Can you think of a plant with medicinal and culinary attributes, yet it’s often toxic to livestock? The weed in question is perilla mint ( Perilla frutescens). Perilla mint is becoming more and more common in pastures across West Virginia, causing concern for some.
Sometimes known as beefsteak plant, Chinese basil or purple mint, perilla mint was introduced from East Asia for its ornamental and culinary values. Usually, animals do not consume this plant, but poisoning can occur when more desirable plants are in short supply. After consumption, livestock can develop symptoms related to respiratory distress such as acute inflammation of the lungs, causing fatality in some.
Perilla mint is an annual weed prevalent in pastures, periphery of woodlots and occasionally, in gardens and other disturbed fields. It can be easily identified by its ribbed, square stems and broad leaves, arranged oppositely with a toothed margin. The leaves vary in color from green to purple, especially when found growing in the shade, and boast a minty aroma when crushed.
It produces a spindly, hairy spike (raceme) bearing purple or white flowers in pairs. It comes to bloom from July to October and is especially toxic to animals when in bloom. Although not all varieties of perilla mint are considered toxic to animals, and its toxicity can vary due to environmental conditions, this plant must be controlled in pastures or other areas frequented by animals.
Perilla mint is most susceptible to control during the spring months when the plants are young and actively growing. Once they come to bloom, the plants become hardy and more difficult to control. As an annual, it can be removed mechanically by taking advantage of its shallow root system. Herbicides, such as 2,4-D (low-volatile ester formulations) or tank-mixtures containing both 2,4-D and dicamba (several formulations) along with a surfactant, provide good control when applied in early spring. Herbicides containing aminopyrlid (Milestone, Grazon Next) also provide effective control, but may persist in treated hay and in manure derived from animals that were fed with treated forage or hay.Author: Rakesh Chandran, WVU Extension Weed Science Specialist
Last Reviewed: July 2018
Recommendations for the use of agricultural chemicals are included as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services does not imply endorsement by West Virginia University Extension Service nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your county Cooperative Extension agent.