White Horse-nettle (Solanum elaeagnifolium) — identification, habitat & look-alikes

White horse-nettle, better known as silverleaf nightshade, is a prickly, silvery-gray perennial with violet star-shaped flowers and yellow berries. It is native to the Southwest and southern Great Plains but is a hard-to-kill weed of farms and rangeland, listed as noxious in 21 states.

Appearance

Appearance: Usually 1–3 ft (30–90 cm) tall and much-branched. Dense star-shaped hairs make the leaves and stems look silvery or pale yellowish green, and stems often carry small tan to reddish prickles. Plants in humid regions may have few or no prickles.
Leaves: Narrow, lance-shaped leaves up to 6 in (15 cm) long, with wavy or shallowly lobed edges, arranged alternately.
Flowers: Showy star-shaped flowers about 3/4–1 1/4 in (2–3 cm) across, deep violet to pale blue or sometimes white, with a column of yellow in the center.
Flowering time: Spring through fall; in California, May through September.
Fruit: Round berries about 1/4–5/8 in (0.6–1.5 cm) wide ripen yellow to orange and can hang on through winter, drying brown. In Texas, fruits are present from May to October.

Look-alikes

Carolina horsenettleSolanum carolinense

Carolina horsenettle has wider, more deeply lobed leaves that are green rather than silvery.

Why they get mixed upBoth are prickly nightshades with similar flowers and yellow berries, and both get called horsenettle.

Western horsenettleSolanum dimidiatum

Western horsenettle has broader, greener leaves, and the two sides of the leaf base often start at different points on the stalk.

Why they get mixed upA similar prickly nightshade in the same region.

Woolly crotonCroton capitatus

Woolly croton has no prickles and lacks the showy purple star-shaped flowers; when not in bloom the two can look alike.

Why they get mixed upBoth have grayish, hairy leaves.

Where it lives

Typical habitats: Pastures and rangeland
Roadsides
Crop fields
Vacant lots
Range: Native from Kansas south to Louisiana and west through the states along the Mexican border, and also native to Mexico and southern South America. It has spread beyond that range; in California it is common statewide below about 3,900 ft (1,200 m) except the North Coast, Klamath Ranges, and Great Basin.
Preferred conditions: Sunny, dry, disturbed ground: fields, orchards, vineyards, pastures, and roadsides.
Flowering: Flowers May–Sep
Flowers May–Sep

Growing it

Propagation: Spreads by seed and by deep creeping roots. Root pieces less than 1/2 in (1 cm) long can sprout new plants, which is why tilling often spreads it.
Toxicity: The whole plant, including the berries, is poisonous to people and livestock, and stays toxic when dried. Wear gloves when pulling it, since the prickles can irritate skin.

Conservation

IUCN Red List: NENot EvaluatedNot yet assessed
Status: Even though it is native to part of the US, it is listed as a in 21 states, including Arkansas, California, Nevada, and Washington.