Species Profile - Solanum dulcamara

Solanum dulcamara L.

Common Name: Bitter nightshade

Synonyms and Other Names:

Solanum dulcamara var. dulcamara L., Solanum dulcamara var. villosissimum Desv., bitter nightshade, climbing nightshade, climbing bittersweet, blue nightshade, European bittersweet, woody nightshade, deadly nightshade, fellenwort, felonwood, poison berry, scarlet berry, shooting star, violetbloom

Identification: A perennial sprawling vine or semi-woody, erect shrub (Campbell et al. 2010, King County 2010). Young plants have hairy stems and leaves, but mature to have a creamy white, brittle woody base which is about ½ inch thick, and light green, slender stems (King County 2010, OARDC Extension 2013). These hollow stems can grow 6.5 feet, and this species has been found growing 30 feet into trees (Campbell et al. 2010, King County 2007, OARDC Extension 2013).

Leaves are dark green with a purplish tint and are connected to the stem via petioles (stalks) in an alternate pattern (Campbell et al. 2010, OARDC Extension 2013). Leaves can be 1-4 inches long and have smooth edges (King County 2010, OARDC Extension 2013). The smaller leaves are oval shaped with a pointed tip and the larger leaves tend to have three lobes: the terminal lobe is bigger than the two lateral lobes (Campbell et al. 2010). Leaves emit an unpleasant smell when crushed (King County 2010).

The blue-violet (on rare occasions white) flowers are star-shaped with 5 recurved petals that join at the base (OARDC Extension 2013). At the center of each flower are bright yellow fused anthers (Campbell et al. 2010). The flowers, which are ½ inch wide, grow in dropping clusters along that are opposite the leaves on the mains stem (King County 2010, OARDC 2013). Flowers are in bloom from May to November (Campbell et al. 2010).

The thin-skinned berries are round to egg-shaped and less than ½ inch wide (King County 2010, OARDC Extension 2013). As these hanging clusters of berries ripen, they change color from green to orange, and are ripe once they become bright red (Forest Health Staff 2006, King County 2010). Ripe berries contain numerous flattened yellow seeds (King County 2010, OARDC Extension 2013).

All stages of flower and berry development can be found on the same individual plant (King County 2010).

Size: to 2 meters

Native Range: Eurasia.


This map only depicts Great Lakes introductions. Click here for Great Lakes region collection information

Great Lakes Nonindigenous Occurrences: Widely naturalized across the United States, including all states in the Great Lakes region. Widespread in the Great Lakes region by 1843.

Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Solanum dulcamara are found here.

State/Province	First Observed	Last Observed	Total HUCs with observations†	HUCs with observations†
IN	2008	2008	4	Little Calumet-Galien; St. Joseph; St. Joseph; Upper Maumee
MI	1843	2019	44	Au Gres-Rifle; Au Sable; Betsie-Platte; Black-Macatawa; Black-Presque Isle; Boardman-Charlevoix; Brule; Carp-Pine; Cheboygan; Clinton; Great Lakes Region; Huron; Kawkawlin-Pine; Keweenaw Peninsula; Lake Erie; Lake Huron; Lake Michigan; Lake St. Clair; Little Calumet-Galien; Lone Lake-Ocqueoc; Lower Grand; Manistee; Menominee; Northeastern Lake Michigan; Northwestern Lake Huron; Northwestern Lake Michigan; Ontonagon; Ottawa-Stony; Pere Marquette-White; Pigeon-Wiscoggin; Pine; Raisin; Saginaw; Southcentral Lake Superior; Southeastern Lake Michigan; Southwestern Lake Huron; Southwestern Lake Huron-Lake Huron; St. Clair; St. Clair-Detroit; St. Joseph; St. Marys; Tittabawassee; Upper Grand; Western Lake Erie
MN	2008	2016	2	Beaver-Lester; St. Louis
NY	1868	2014	20	Cattaraugus; Chaumont-Perch; Eastern Lake Erie; Great Lakes Region; Indian; Irondequoit-Ninemile; Lake Ontario; Lower Genesee; Niagara River; Northeastern Lake Ontario; Oak Orchard-Twelvemile; Oneida; Oswego; Oswego; Salmon-Sandy; Saranac River; Seneca; Southwestern Lake Ontario; St. Lawrence; Upper Genesee
OH	1982	2013	11	Auglaize; Black-Rocky; Blanchard; Cedar-Portage; Cuyahoga; Huron-Vermilion; Lake Erie; Lower Maumee; Sandusky; Southern Lake Erie; Western Lake Erie
ONT	2011	2014	*
PA	2008	2008	1	Lake Erie
WI	1960	2018	21	Bad-Montreal; Beartrap-Nemadji; Black-Presque Isle; Brule; Door-Kewaunee; Duck-Pensaukee; Fox; Lake Michigan; Lake Superior; Manitowoc-Sheboygan; Menominee; Milwaukee; Northwestern Lake Michigan; Northwestern Lake Michigan; Oconto; Peshtigo; Pike-Root; Southwestern Lake Michigan; Southwestern Lake Superior; Upper Fox; Wolf

Table last updated 2/27/2023

† Populations may not be currently present.

* HUCs are not listed for areas where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Ecology: Occurs in a very wide range of habitats, including wet woods, fence rows, thickets, roadsides, wetalnds, and shorelines (Campbell et al. 2010) (Waggy 2009). In the Great Lakes, it has also been found in grasslands and meadows, as well as in disturbed areas (Waggy 2009). This species can grow and reproduce in sun or shade environments (Pegtel 1985). Climbs onto small trees, shrubs and fences or remains low-growing depending on what is available; can climb 30 feet or higher into trees or form thickets along the ground (King County 2010). Branches grow and die back 3 to 6 feet or more each year (King County 2010).

Bittersweet nightshade flowers from May to November (Campbell et al. 2010). Fruit and seed production can be abundant; each berry can have about 30 seeds (King County 2010). Plants spread to new locations by birds eating the ripe berries and by stem/root fragments moving in soil or water (Campbell et al. 2010, King County 2010, Waggy 2009). New plants are created from a parent plant by way of suckering roots, prostrate stems rooting at nodes, and by growing up and over vegetation or structures like fences and buildings.

Means of Introduction: Deliberate release (EPA 2008).

Status: Established.

Great Lakes Impacts: Solanum dulcamara has a moderate environmental impact in the Great Lakes.
Realized:
Solanum dulcamara, along with other plants in the nightshade family, is poisonous. It produces solanine in its leaves, shoots, and unripe berries. If ingested by animals, it can cause difficult breathing, weakness, dermatitis, gastrointestinal irritation/pain, nervous system problems, and in severe cases death (Forest Health Staff 2006, King County 2010). Bittersweet nightshade also has a strong, unpleasant odor, so most animals will avoid it and poisonings from this plant are not very frequent.

The vines of S. dulcamara can grow over nearby trees and shrubs, and even pull down smaller plants (Forest Health Staff 2006, IPANE 2013). This growing ability can quickly lead to dense thickets of bittersweet nightshade (King County 2010). Solanum dulcamara can also become dominant along small waterways and alter the flow of water (King country 2010).

Bittersweet nightshade is abundant throughout Michigan and Ohio (OARDC Extension 2013, Reznicek et al. 2011). The New York Invasive Species Council ranks this species at moderate ecological risk (New York Invasive 2010). Falck and Garske (2002) acknowledge that, given this species' small size and ability to thrive in forested areas, data about its presence is likely underrepresented.

Potential:
In studies conducted in New Zealand, species within the Solanum genus showed resistance to hybridization (Armstrong et al. 2005). This indicates that S. dulcamara may pose only a small genetic threat to native or crop species.

Water extract from the leaves of S. dulcamara significantly inhibited the growth of Pinus resinosa seedlings; however, this allelopathy has not been studied in the field (Waggy 2009).

Solanum dulcamara has a moderate socio-economic impact in the Great Lakes.
Realized:
All portions of this plant are poisonous (Forest Health Staff 2006). It has been reported that paralysis can occur in humans after consuming only 6 berries (OARDC Extension 2006). Poisoning from S. dulcamara has been reported in cattle, sheep, and horses (OARDC Extension 2006).

Potential:
Bittersweet nightshade can act as a host for Leptinotarsa decemlineata (Colorado potato beetle). This beetle can invade species from the Solanaceae family, such as potatoes and tomatoes, and could damage the crops (IPANE 2013, OARDC Extension 2006). However, success of beetles reared on S. dulcamara varied depending on seasonally varying phytochemicals present in the plant (Hare 1983). Solanum dulcamara can also host two other pathogens: Phytophthora infestans (causes potato blight) and Ralstonia solanacearum (causes brown rot in potatoes) (Golas et al. 2010, Knapp 2013).

There is little or no evidence to support that Solanum dulcamara has significant beneficial effects in the Great Lakes.
Realized:
Extracts from the roots, bark, and stems of S. dulcamara have been used to relieve pain caused by rheumatism, poor circulation, ulcers, and skin afflictions. Currently, these extracts are not widely used (Waggy 2009).

Potential:
Solanum dulcamara contain glycosides; which can be used in the production of steroidal hormones (Curtis et al. 2000).

Alcoholic extracts of S. dulcamara, taken from plants grown in New York and Wisconsin, exhibited tumor-inhibitory activity in mice (Kupchan et al. 1965).

Management: Regulations (pertaining to the Great Lakes)
After determining that S. dulcamara poses a low ecological impact, the Nature Conservancy gave this species a “low” national priority ranking (NatureServe 2009). The New York Invasive Species Council determined that this species poses a moderate ecological risk, and therefore recommended that this species be regulated (New York Invasive 2010).

As of 2011, the Great Lakes Indian Fish & Wildlife Commission ranked S. dulcamara as a “lower priority” (Falck et al. 2012).

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control
Biological
There are no known biological control methods for this species (King County 2010).

Physical
Solanum dulcamara may be controlled by manually digging up the roots; most effective with the plants are young and the soil is moist (Waggy 2009). All parts of the roots should be removed to prevent regrowth (King County 2010). Gloves should be worn when handling this species to prevent skin irritation (King County 2010).

Mowing is not a practical method for control because this species can resprout from the suckering roots and rhizomes; however it may be useful when manually removing the root system (King County 2007). If mowing is the only option, it must be done several times during the growing season to be effective (Forest Staff Health 2006). Another option would be to cover the cut plants with a heavy geotextile cloth for two years to prevent photosynthesis and regrowth (King County 2010).

Chemical
Larger infestations may require the use of an herbicide (Forest Staff Health 2006). The herbicide Clopyralid (Transline®, Stinger®, Reclaim®, and Curtail®) is effective on Solanaceae (Tu et al. 2001).
Triclopyr is effectively taken up in the woody stems, roots, and leaves of bittersweet nightshade. It is also unlikely to harm nearby grasses, sedges, rushes, cattails, lilies, and irises (King County 2010).

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.

References: (click for full references)

Armstrong, T. T., R.G. Fitzjohn, L.E. Newstrom, A.D. Wilton, and W. G. Lee. 2005. Transgene escape: what potential for crop-wild hybridization? Molecular Ecology 14: 2111—2132.

Campbell, S., P. Higman, B. Slaughter, and E. Schools. 2010. A Field Guide to Invasive Plants of Aquatic and Wetland Habitats for Michigan. Michigan DNRE, Michigan State University Extension, Michigan Natural Features Inventory. 90 pp.

Curtis, I. S., J.B. Power, P. Heddens, A. Phillips, K.C. Lowe, D.A. Wards, and M. R. Davey. 2000. Transformation and characterization of transgenic plants Solanum dulcamara L. -- Incidence of transgene silencing. Annals of Botany 86: 63—71.

Falck, M. and S. Garske. 2002. Invasive Non-native Plant Management During 2001. Odanah, WI. 32 pp.

Falck, M., W. Gilane, and R. Parisien. 2012. Invasive Species Program 2011. Great Lakes Indian Fish & Wildlife Commission, Odanah, WI. 27 pp.

Forest Health Staff. 2006. Bittersweet Nightshade: Solanum dulcamara L., USDA Forest Service. 1 pp.

Golas, T. M., G.M. van der Weerden, R.G. van den Berg, C. Mariani, and J. J. H. M. Allefs. 2010. Role of Solanum dulcamara L. in potato late blight epidemiology. Potato Research 53:69—81.

Hare, J. D. 1983. Seasonal variation in plant-insect associations: utilization of Solanum dulcamara by Leptinostarsa decemlineata Ecology 64(2): 345—361

Invasive Plant Atlas of New England (IPANE). 2013. Bittersweet Nightshade: Solanum dulcamara L. Available http://www.eddmaps.org/ipane/ipanespecies/vines/Solanum_dulcamara.htm. Accessed 12 April 2013.

Kings County Noxious Weed Program. 2007. Weed Alert: Bittersweet Nightshade. 2 pp.

Kings County Noxious Weed Program. 2010. Best Management Practices: Bittersweet Nightshade. 10 pp.

Knapp, S. 2013. Solanum dulcamara. Natural History Museum. Available http://www.nhm.ac.uk/nature-online/species-of-the-day/collections/collecting/solanum-dulcamara/index.html. Accessed 12 April 2013.

Kupchan, S. M., S.J. Barboutis, J.R. Knox, and C. R. L. Cam. 1965. Beta-Solamarine: Tumor inhibitor isolated from Solanum dulcamara. American Association for the Advancement of Science 150(3705): 1827—1828

Missouri plants. Solanum dulcamara. Accessed on 2008-10-26. http://www.missouriplants.com/Bluealt/Solanum_dulcamara_page.html

NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life. Version 7.0. Arlington, VA: NatureServe. Available http://www.natureserve.org/explorer.

New York Invasive Species Council. 2010. Final report: a regulatory system for non-native species. Department of Environmental Conservation, Albany, NY. 131 pp.

OARDC Extension; The Ohio State University. 2013. Bittersweet Nightshade: Solanum dulcamara. Available http://www.oardc.ohio-state.edu/weedguide/singlerecord.asp?id=730. Accessed 12 April 2013.

Pegtel, D. M. 1985. Germination in populations of Solanum dulcamara L. from contrasting habitats. New Phytologist 100: 671—679.

Reznicek, A. A., E. G. Voss, & B. S. Walters. 2011. Michigan Flora Online. University of Michigan. Available http://michiganflora.net/species.aspx?id=2710. Accessed 12 April 2013.

Tu, M., C. Hurd, and J. M. Randall. 2001. Weed Control Methods Handbook: Tools and Techniques for Use in Natural Areas. The Nature Conservancy; Wildland Invasive Species Team. 219 pp.

U.S. Environmental Protection Agency (EPA). 2008. Predicting future introductions of nonindigenous species to the Great Lakes. Washington DC. 138 pp.

Waggy, M. A. 2009. Solanum dulcamara. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Available http://www.fs.fed.us/database/feis/plants/shrub/soldul/all.html. Accessed 12 April 2013.

Other Resources:

USDA/NRCS PLANTS Database

http://www.kingcounty.gov/environment/animalsAndPlants/noxious-weeds/weed-identification/bittersweet-nightshade.aspx

Author: Cao, L, and L. Berent

Contributing Agencies:

Revision Date: 8/15/2019

Citation for this information:
Cao, L, and L. Berent, 2023, Solanum dulcamara L.: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/GreatLakes/FactSheet.aspx?NoCache=8%2F2%2F2011+7%3A23%3A37+AM&Species_ID=2665&State=&HUCNumbe, Revision Date: 8/15/2019, Access Date: 6/8/2023

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.