Horsenettle (Solanum carolinense)
Horsenettle is a Southeastern native, perennial weed and a member of the nightshade or Solanaceae family. The nightshade family also includes tomatoes, peppers, eggplant, and potato. This presents a problem for home gardeners because this weed and other nightshade weeds can serve as alternate hosts for leaf spot diseases, viruses and a host for the Colorado potato beetle. The Colorado potato beetle primarily attacks potatoes and eggplant but will occasionally feed on tomatoes and peppers.
Horsenettle has thorns along the stems, coarsely lobed leaves with spines along prominent veins, and the plant is poisonous. The yellow fruits are toxic and are poisonous to people, horses, cattle, cats, and dogs. The flowers can be either purple or white. This plant is found in dry, disturbed sites like open woods and roadsides.
Horsenettle spreads by seed and by rhizomes. The fruits contain up to 170 seeds each, making each plant capable of producing over 5000 seeds each year. The rhizomes can extend for up to three feet and produce new shoots. New plants can also develop from root fragments left in the soil. Tilling will exasperate this problem, as will hand pulling. Roots can travel down several feet in the soil in the search for water.
Chemical control is the best option to manage this weed. Several broadleaf weed killers can provide effective control. Please consult with your local extension office or contact the HGIC at firstname.lastname@example.org for recommendations specific to your site.