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Nature Guide






















climbing nightshade (Solanum dulcamara)





















bittersweet nightshade
bitter nightshade
climbing nightshade
European nightshade


SCIENTIFIC SYNONYMS: There are no scientific synnyms for Solanum dulcamara.


CONFIRMATION STATUS: Pending confirmation.


TAXONOMY: The currently acccepted scientific name for climbing nightshade is Solanum dulcamara. Two varieties are recognized in North America: 1) Solanum dulcamara L. var. dulcamara, and Solanum dulcamara L. var. villosissimum Devs. Specimens found in Sky Meadows State Park are believed to be variety dulcamara.


NATIVE STATUS: Introduced, United States and Canada.




Habit: Bittersweet nightshade is a perennial, rhizomatous vine or scrambling shrub. Its base is woody, and the aboveground branches are herbaceous and die back each year. Aboveground stems are typically about 10 feet (~3 m) long, sometimes growing as long as 23 feet (~7 m). Bittersweet nightshade's stems can twine over other plants, trail along the ground, or grow erect.


Stems are many branched, hairless to sparsely hairy, and lack tendrils, the stems climbing up anything nearby or becoming bushy depending on the particular site. Prostrate stems root at the nodes, the roots can sucker profusely, creating sizable patches. Lower stems are woody, the leafy branches dying back each year.


Leaves: Leaves are 1¼ to 4 inches long, ¾ to 2½ inches wide, generally egg-shaped tapering to a pointed or blunt tip, smooth to sparsely hairy, toothless, with a stalk up to ¾ inch long. Most leaves have 2 small lobes (one to two rarely three) at the base of the leaf that do not quite appear to be part of the blade. These wing-like lobes are placed alternately on either side of the stem and arranged so that they face the light. The flower-clusters always face a different direction to the leaves.


Flowers: Branching clusters of stalked flowers arising from leaf axils and at the tips of branching stems. Flowers are ½ inch across, 5 purple petals that are flaring to tightly curled back. Protruding like a missile in the center is a yellow column of stamens with a slender style extending at the tip. The calyx has 5 short triangular lobes; the calyx and stalk are smooth to sparsely hairy.


Its inflorescence is a drooping cyme or panicle, typically having 7 or more flowers, sometimes as many as 30. Its fruit is a berry, 2 to 8 mm in diameter. Bittersweet nightshade seeds are 2 to 3 mm x 1.7 to 2.5 mm and are strongly flattened.


Fruits/Seeds: Fruit is a ¼-inch, green, oval to egg-shaped berry that ripens to shiny red. In North America, bittersweet nightshade berries are produced throughout summer and fall and may remain on the plant until winter.


Roots: Bittersweet nightshade spreads by rhizomes. The main root grows horizontally just below the soil surface, sprouts frequently, and can branch 3 to 5 times. Roots of bittersweet nightshade have secondary growth and an epidermis that is protected by a layer of suberin at the root cap. Feeder roots are 100 to 500 µ in diameter and sprout root hairs that grow up to 400 µ.


The roots of bittersweet nightshade can be colonized by mycorrhizal fungi, albeit poorly, and classified bittersweet nightshade as facultatively mycorrhizal. Species classified as facultatively mycorrhizal may benefit from a mycorrhizal association but are not dependent on it.


REGENERATION PROCESS: Bittersweet nightshade spreads vegetatively by creeping stems that root at the nodes and by rhizomes. It sprouts from the base when cut or damaged.


HABITAT TYPES: Climbing nightshade disturbed forests and forest edges, clearings, old fields, fencerows, disturbed alluvium, and tidal marsh edges, river banks, floodplains, swamps, canals, ditches, mires and marshes, and damp woods.. In Virginia, Climbing nighthad is frequent in the mountains; infrequent in the Piedmont; rare in the Coastal Plain.


SITE CHARACTERISTICS: Bittersweet nightshade occurs in habitats ranging from full sun to deep shade. This may one factor that has contributed to its extensive range as an introduced species.


Bittersweet nightshade occurs in a variety of soil types and textures, including shallow soils consisting mostly of humus and is more likely to occur on sites with higher percentages of sand. It also occurs in riparian deciduous forest characterized by deep, well drained, gravelly loam.


Bittersweet nightshade occurs on sites with a range of soil pH. It has ben reported that it occurs on soils with pH ranging from 7.2 to 8.29. Additional information suggests that bittersweet nightshade can tolerate lower pH. Bittersweet nightshade may prefer soils rich in nitrogen.


Bittersweet nightshade occurs in riparian areas and is most commonly associated with cottonwood (Populus spp.), native willow (Salix spp.), and alder. It often occurs on disturbed sites with other nonnative or invasive species including eggleaf spurge (Euphorbia oblongata), Canada thistle (Cirsium arvense), common St. Johnswort (Hypericum perforatum), Himalayan blackberry (Rubus discolor), Russian-olive (Elaeagnus angustifolia), tamarisk (Tamarix spp.), and reed canarygrass.


SEASONAL DEVELOPMENT: The blooming period usually occurs during the summer and lasts 2-3 months.


GENERAL DISTRIBUTION: Climbing nightshade is an introduced species that can be found throughout the New England and Mid-Atlantic states, and has extended its range through the Ohio Valley, Mid-West and Upper Mid-West, Rocky Mountain, and far western Pacific states. It has yet to be recorded in most of the Gulf Coast states although is has been observed in Florida and Georgia.




IMPORTANCE AND USES: Although bittersweet nightshade is nonnative in North America, reviews indicate that it has food and cover value for wildlife, but it has not been reported as a major food source for any species with the exception of bumblebees.


Birds typically digest the fleshy portion of bittersweet nightshade's fruit and expel the seed (see Seed dispersal). Birds adapted to foraging in vegetation, which can reach fruit while perched on a branch and are not restrained by a small gape, are more likely to eat bittersweet nightshade fruit than birds lacking these characteristics. Frugivorous birds such as crows, eastern kingbirds, mimic-thrushes, thrushes, white-crowned sparrow, and waxwings eat the fruits of bittersweet nightshade. Numerous other songbirds and upland gamebirds throughout the United States also eat bittersweet nightshade fruit, especially in the Northeast and Southwest. Ring-necked pheasants eat the fruit of bittersweet nightshade, especially as an emergency food source during ice storms. In the United Kingdom, bittersweet nightshade fruit is the primary food for blackcaps, review by and is also used by blackbirds, song thrush, robin, starling, and spotted flycatcher. Bullfinches are the only known bird that regularly eats bittersweet nightshade fruit for its seed rather than its flesh (review by.


Mammals that occasionally eat bittersweet nightshade fruit include black bear, Virginia opossum, eastern cottontail rabbits, and white-tailed deer. Common muskrats graze on the stems of bittersweet nightshade. Herbivory by invertebrates on bittersweet nightshade has been reported in North America.


While not preferred, bittersweet nightshade is occasionally used for nesting. Gray catbirds in the central portions of North America and Ontario, Canada, occasionally (< 1% of their nests) built nests in bittersweet nightshade. American eiders nesting along Maine's Penobscot Bay occasionally used bittersweet nightshade; however, nesting success (i.e., percent hatched) was lower in nests constructed in bittersweet nightshade than in nests constructed in most native vegetation.


Bittersweet nightshade has been studied primarily for its secondary chemicals and used for its medicinal properties. Bittersweet nightshade contains small amounts of compounds that have been studied for their potential medicinal importance. In North America bittersweet nightshade was widely prescribed for its narcotic, diuretic, alterative, and cleansing principles during the latter half of the nineteenth century. It was thought to relieve many ailments including leprosy, skin diseases, cutaneous diseases, rheumatic infections, ulcers, sores, and gland swelling. Although bittersweet nightshade is not widely used today, extracts from its roots, bark, and shoots are still prescribed for their narcotic principles in rheumatism, circulation, ulcers, and skin afflictions.


Bittersweet nightshade has been cultivated for ornamental purposes, and seeds are still available for purchase from online distributors. However, a review on seeds suggests that any ornamental values of bittersweet nightshade are offset by its poisonous properties.



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