Invasive Watch: Horsenettle

Picture of Horsenettle

How to Identify Horsenettle

Featuring prickly stems that can grow up to 3 feet high, horsenettle (Solanum carolinense) is a member of the nightshade family that is distinguished by clusters of star-shaped flowers with five white or violet petals surrounding a yellow center. This perennial herbaceous plant has alternating oblong leaves that are hairy and commonly exceed 4 inches in length. When crushed, horsenettle leaves emit a potatolike odor.

As part of the plant’s natural defenses, horsenettle produces a toxic tomatolike fruit that turns from green to yellow as it matures and often contains over 150 disk-shaped seeds. The berries are borne in clusters and grow to about ½ inch in diameter. Much like the rest of the plant, horsenettle fruit is notably poisonous, making it a threat to livestock and other animal species.

Where Is Horsenettle Found?

As one of the most difficult weeds to eradicate, horsenettle is native to the southeastern United States. It can be most commonly found throughout a variety of natural areas, including fields, pastureland and roadsides. While the plant is known to grow most often in gravelly or sandy soils, it is capable of developing in alternative soil types and thrives in temperate climates.

The plant’s underground rhizomes aid vegetative reproduction, and horsenettle seeds can spread through a variety of carriers to introduce the noxious weed to new areas.

How to Treat Horsenettle

Most attempts to control this perennial weed are futile as it is known to resist many postemergence and broad-spectrum herbicides. The horsenettle root system is comprised of deeply penetrating vertical roots that can stretch to nearly 10 feet in length, so flame weeding is ineffective. Frequent mowing can weaken the plant’s roots, but such practices can take years to kill horsenettle invasions. Ultimately, the most effective and timely method of control for this noxious weed is selective herbicide applications. 

Vegetation managers can use TerraVue™ herbicide to effectively treat areas in which horsenettle and other broadleaf weeds or brush species have developed. As a selective herbicide that is safe on grass and most beneficial forbs, TerraVue offers effective horsenettle control during the late summer or fall. When applying TerraVue, a rate of 2 to 2.85 ounces per acre can be used to treat affected areas. However, applicators should check the product label for appropriate usage rates to ensure optimum results and controlled efficacy.

 

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™ ® Trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. When treating areas in and around roadside or utility rights-of-way that are or will be grazed, hayed or planted to forage, important label precautions apply regarding harvesting hay from treated sites, using manure from animals grazing on treated areas or rotating the treated area to sensitive crops. See the product label for details. TerraVue™ is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.

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