Bittersweet nightshade (Solanum dulcamara)

Common Names: climbing nightshade, woody nightshade, European bittersweet, blue nightshade, scarlet berry, snakeberry, fellonwort, felonwood, violet bloom, wolfgrape, devil's apple, blue blindweed, poisonous nightshade

Description:

Bittersweet nightshade (Solanum dulcamara) is an invasive vine from Europe and Asia that was introduced to North America for ornamental and medicinal use and had spread widely by the late 1800s [1][2]. It scrambles over native shrubs and trees in wet, shady places and forms dense patches that crowd out native plants [3]. MISIN tracks it because all parts of the plant are poisonous to people, pets, and livestock, and because it spreads easily by bird-dropped berries and creeping roots.

Habit:

Bittersweet nightshade is a perennial vine with a woody base and softer green branches that climb or sprawl. The stems usually run about 3 to 10 feet long, but can reach 20 feet or more when climbing into trees [3]. The leaves are dark green, often with a purple tint, and many have two small lobes or "ears" near the base that make the leaf look almost arrow-shaped [4][5]. From late spring through fall the plant carries small purple star-shaped flowers with a bright yellow center, followed by drooping clusters of berries that ripen from green to orange to glossy red [4][5].

The easiest time to spot it is mid- to late summer and into fall, when the purple flowers and red berries often appear on the vine at the same time ? a combination no native look-alike shows. A bruised leaf or stem gives off a strong, unpleasant odor [5]. Look for it draping over shrubs and fences in damp, partly shaded spots.

At-a-glance cues:

1. Climbing or sprawling vine with a woody base and green upper branches [3]
2. Many leaves have two small lobes near the base, like little ears [4]
3. Purple star-shaped flowers with a pointed yellow center, in drooping clusters [4][5]
4. Berries hang in clusters and ripen green to orange to shiny red; flowers and red berries often appear together [5]

Leaves:

1. Arrangement: alternate along the stem [4]
2. Shape: egg-shaped to triangular; larger leaves often have two small lobes or "ears" near the base, while smaller leaves are unlobed [4][5]
3. Margin: smooth (no teeth) [4]
4. Surface: dark green, often purple-tinged; smooth to slightly hairy; gives off a strong unpleasant smell when crushed [4][5]
5. Size: roughly 1 to 4 inches long [4]

Stems:

1. Habit: perennial vine; woody at the base, with green to greenish-brown softer branches above that climb or scramble [3][5]
2. Young stems are often purple and finely hairy, turning brown and woody with age [5]
3. No tendrils ? the plant leans and scrambles rather than grips [5]
4. Upper branches die back toward the woody base each winter [3]

Flowers:

1. Color: purple to blue-violet, with a cone of bright yellow stamens in the center [4][5]
2. Shape: star-shaped, about 1/2 inch across, with five petals that curve backward [4][5]
3. Arrangement: loose, drooping clusters of roughly 6 to 30 flowers [3][5]
4. Bloom time: late spring through fall (about May to September) [3]
5. Sex: flowers are "perfect" ? each has both male and female parts [3]

Fruit and seeds:

1. Fruit type: small, egg-shaped to round berry, about 1/3 to 1/2 inch long, in drooping clusters [4][5]
2. Color: ripens from green through orange to glossy bright red [4][5]
3. Ripening: summer into fall; berries often hang on the vine into winter [3]
4. Dispersal: birds and mammals eat the berries and spread the seeds in their droppings [3]
5. Seeds: roughly 30 to 60 small, flat, yellowish seeds per berry [3][5]

Habitat:

Bittersweet nightshade grows best in damp, partly shaded ground. It is most common along streambanks, pond and marsh edges, wetlands, moist woods, thickets, fence rows, roadsides, and disturbed areas near buildings [3][4]. It tolerates a wide range of conditions ? full sun to deep shade, and soils from sandy to clay, including ground that floods seasonally [3]. It is native to Europe, North Africa, and temperate Asia, and is now naturalized across most of the United States and Canada, with the Great Lakes region, the Northeast, and the Pacific Northwest among the areas where it is most common [3][6]. It does best on rich, moist, nitrogen-rich soils but adapts to far drier sites as well [3].

Reproduction:

Bittersweet nightshade spreads in two main ways, and a homeowner is most likely to see it arrive by the first. Birds ? including robins, thrushes, and waxwings ? eat the red berries and drop the seeds wherever they perch, so new plants often appear under trees, along fences, and at the edges of yards [3]. The plant also creeps outward by underground stems (rhizomes) and by branches that root where they touch the ground, so a patch in a neighbor's yard or a nearby wetland can slowly spread onto your property [3]. Cut or broken stem and root pieces can take root and start new plants, which is why careless removal can make a patch worse [3].

Each berry holds roughly 30 to 60 seeds, and an established plant in good light produces berries in large numbers [3][5]. Most seeds sprout the following spring rather than waiting years in the soil [3]. For control timing, this means the key is to stop berries from forming: pull or cut plants before or during flowering in late spring and summer, and remove any berries before birds carry them off [3].

Impact and Damage:

The most important thing for a homeowner to know is that every part of bittersweet nightshade is poisonous. The plant contains solanine and related compounds, and the unripe green berries are the most toxic part. Children are the most common human poisoning cases, drawn to the bright berries; eating them can cause an upset stomach, vomiting, drowsiness, and ? in large amounts ? more serious effects. The plant is also toxic to dogs, horses, and livestock, causing drooling, vomiting, diarrhea, weakness, and trouble breathing[7]. Keep children and pets away from the berries, and wear gloves when handling the plant.

In gardens and natural areas, the vine scrambles over shrubs and small trees and can form dense patches that shade out and crowd native plants [3]. Its impact is usually greatest along streambanks and wetland edges, where it is most abundant and can grow over native shrubs like dogwoods and willows [3]. Across most upland forests its impact is rated low to moderate, and it tends to thin out as a forest canopy closes in [3]. The plant can also serve as a wild host for pests and diseases of cultivated potato and tomato, including the late blight pathogen Phytophthora infestans, though natural infections in the wild are uncommon and its role in crop disease appears minor [8].

Similar species:

Eastern black nightshade (Solanum ptychanthum) is a close relative that is easily confused with young bittersweet nightshade because both have small star-shaped flowers and similar leaves. You can tell them apart by growth and fruit: black nightshade is an upright annual that dies each year and has dull black berries, while bittersweet nightshade is a climbing perennial vine with glossy red berries [5][9].

American bittersweet (Celastrus scandens) and Invasive bittersweet (Celastrus orbiculatus) are often mixed up with this plant because they share the "bittersweet" name, but they are unrelated woody vines from a different plant family. They have rounded leaves and orange-and-red capsule fruits that split open, not the purple star flowers or soft red berries of bittersweet nightshade [5][10].

Monitoring and rapid response:

Signs to watch for:

1. Vines scrambling over shrubs, fences, or the ground in damp, partly shaded spots, especially near water [3][4]
2. Purple star-shaped flowers with yellow centers from late spring through fall [4]
3. Drooping clusters of red berries in summer and fall ? often on the same vine as the flowers [5]
4. New seedlings under trees, along fences, and at yard edges where birds perch

What you can do:

1. Wear gloves ? all parts are toxic. Hand-pull or dig out young plants and small patches, ideally in spring or after rain when the soil is loose [3].
2. Remove the whole root system. Broken root and stem pieces can resprout, so dig carefully rather than yanking the top off [3].
3. Cut and bag any berries before birds spread them, and put plant material in the trash rather than composting it [3].
4. For larger areas, natural area crews can work outward from the smallest, newest patches first, repeat-visit a site over the season to catch resprouts, and follow removal by replanting native shrubs and monitoring for several years [3].

When to call a professional:

1. Large or long-established patches with thick woody bases and deep, spreading roots that resprout after cutting [3]
2. Infestations along streambanks, pond edges, or wetlands, where work near water needs special care [3]
3. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. USDA NRCS PLANTS Database. Solanum dulcamara L. (climbing nightshade). plants.usda.gov
2. Plants of the World Online. Solanum dulcamara L. Royal Botanic Gardens, Kew. powo.science.kew.org
3. Waggy MA (2009). Solanum dulcamara. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. fs.usda.gov
4. North Carolina Extension Gardener Plant Toolbox. Solanum dulcamara. NC State Extension. plants.ces.ncsu.edu
5. Hilty J. Bittersweet Nightshade (Solanum dulcamara). Illinois Wildflowers. illinoiswildflowers.info
6. USGS Nonindigenous Aquatic Species. Solanum dulcamara ? Great Lakes species profile. nas.er.usgs.gov
7. Cerna M, Kotyzova D, et al. (2015). "Successful treatment of Solanum dulcamara intoxication in a Labrador retriever puppy." Veterinary Medicine (Praha) 60(8):447?451. pmc.ncbi.nlm.nih.gov
8. Golas TM, van de Geest H, et al. (2010). "Role of Solanum dulcamara L. in potato late blight epidemiology." Potato Research 53:155?166. semanticscholar.org
9. Friends of the Wild Flower Garden. Black Nightshade (Solanum nigrum / Solanum ptycanthum). friendsofeloisebutler.org
10. Friends of the Wild Flower Garden. Climbing Nightshade (Solanum dulcamara). friendsofeloisebutler.org

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