Nightshades are plants in the Nightshade family (Solanaceae), especially those in the genus Solanum or those with similar-looking flowers. Most of them are poisonous if eaten, although potatoes and tomatoes are both nightshades that have some edible parts.
One nightshade species in the Solanum genus is native to West Sacramento, and three others are native to other parts of Yolo County.
American Black Nightshade (Solanum americanum), alternatively known as White Nightshade, is a three- to four-foot-tall herbaceous annual or short-lived perennial that is native to all of West Sacramento and all the low-lying flatlands of Yolo County. An occasional volunteer in West Sacramento gardens, it produces white flowers and black fruit. It prefers full sun and significant moisture. It is commonly eaten or used medicinally in may countries, particularly in Africa and in various Pacific Islands, including among Indigenous Hawaiians.
Parish's Purple Nightshade (Solanum parishii) is a shrub that is native to the far western edge of Davis and the western two thirds of Woodland, as well as to the Dunnigan Hills, the Capay Hills, the Yolo County foothills, and the flatlands west of Davis and Woodland. It grows a little over three feet tall and up to five feet wide. It prefers full sun or partial shade and needs very little water. All parts of this plant, but especially the fruits, are poisonous to humans and to some other animals.
Blue Witch Nightshade (Solanum umbelliferum) is a shrub (occasionally slightly vining) that is native to the Dunnigan Hills, the Capay Hills, the Yolo County foothills, and some flatlands west of Woodland, including Esparto, Madison, and Monument Hills. It grows up to three feet tall and three feet wide but often stays less than half that size. It prefers full sun or partial shade and needs very little water. It goes summer-deciduous under drought stress but doesn't need much water to keep its leaves. All parts of this plant, but especially the fruits, are poisonous to humans and to some other animals.
Chaparral Purple Nightshade (Solanum xanti) is a semi-evergreen small vine or prostrate shrub that is native to the Yolo County foothills, including the the Capay Hills. It grows two to four feet long but does not achieve height without a support to climb up. All parts of this plant, but especially the fruits, are poisonous to humans and to some other animals.
Two other plants in other genera of the Nightshade family are native to West Sacramento, and one is native to other parts of Yolo County.
Indian Tobacco (Nicotiana quadrivalvis) is a four- to seven-foot-tall annual herb that is native to the northern third of West Sacramento. It prefers full sun. Its flowers are usually white, sometimes pale yellowish green or pale purple. It is a source of nicotine, which functions as an insecticide to defend it against insects that eat it.
Sacred Thorn-Apple (Datura wrightii) is a five-foot-tall and at least equally wide perennial herb that is native to the northeastern third of West Sacramento, often growing in dry, disturbed soil. From April to October each year, it produces luminous eight-inch white flowers (often edged with pale purple) that open at sunset and wither soon after next sunrise. These flowers are followed by round, spiky seedpods (thorn-apples) containing numerous seeds that germinate readily. Then it dies to the ground every winter. This plant is sometimes used as a hallucinogen and is quite dangerous when used that way, particularly because it gives users the impression that they are unimpaired even when nothing they see is actually real. Users are at high risk of being hit by cars due to suffering transitory blindness while under the belief that they still have normal vision.
Sharpleaf Ground-Cherry (Physalis acutifolia) is a three-foot-tall annual herb that is native along the I-5 corridor at the far north end of Yolo County, and also in Davis. It often grows in disturbed soil. Its fully ripe fruits (ground-cherries) are edible raw or cooked.