Latin Name: Solanum dulcamara
Physical Description: It is a perennial vine or semi-woody shrub, from a rhizome. The stems are shrubby below and grow up to 3 m long. Leaves are dark-green to purplish, 2 cm to 10 cm long and often have one or two small ear-like lobes near the base. The flowers are star-shaped with stamens fused in a prominent yellow cone. It produces berries that are round or egg-shaped, green when immature and bright red when ripe. The main root grows horizontally just below the surface and suckers frequently.
Habitat: It prefers moist to mesic areas and is often found along lakes, streams, rivers, creeks and wetlands, as well as field edges, gardens, parks, and roadsides.
Impacts: This plant contains solanine and is toxic to people, pets, and livestock. It has a strong, unpleasant odor, so most animals will avoid it, and poisonings from this plant are not very frequent. It is also highly competitive and can become so prolific that it is grows out into creeks, rivers and streams, creating a false gravel beds and interfering with fish movement. It is can out-competing native shrubs and even small trees such as willows and alders.
Reproduction: It reproduces through seed and vegetatively through rhizomes and by creeping stems that root at the node. Each fruit can produce 40 to 60 seeds and are often dispersed by bird’s consuming the fruit.
Mechanical: Small, immature, infestations can be hand pulled or dug if extreme care is taken to remove the entire root system. Root fragments that have been left in the soil will most likely grow into new plants and may make the infestation worse. It’s best to carry out pull or dig plants after rain or in loose soils. Mowing is not usually practical because of its growth form and habitat. Cutting plants to the ground can be combined with covering with heavy duty geotextile fabric (woven plastic fabric) or other sheet mulching materials. Covering needs to be kept securely in place for at least two years and should be checked several times a year for any emerging stems around edges or through gaps.
Chemical: Several herbicides with the following active ingredients can control Bittersweet nightshade: glyphosate, imazapyr, and tryclopyr. For available products, contact your local agri-supply store. Prior to any herbicide application, read and follow the label instructions
Biological: Not available.
King County’s Best Management Practices for Bittersweet Nightshade