Photo Courtesy of Dave Powell, USDA Forest Service, http://www.bugwood.org/
Growth Characteristics: A low-growing member of the Evening Primrose family, Yellow Evening-primrose bears quite a resemblance to the Dandelion, growing in dense tufts. It is sparsely covered with minute, straight, stiff hairs, or nearly glabrous.
Flowers: Yellow evening primrose flowers are about 1 ½ - 2 inches in diameter. The flowering stem is 4 inches tall, and does not exceed the length of the leaves. The flowers open in the evening and are solitary at the tips of flower stalks. The calyx is actually purplish, with slightly fused lobes. The petals are yellow, aging to purplish, and are ½ to ¾ inch long.
Fruits/Seeds: Capsules which are conspicuously 4-winged, ½ to ¾ inches long.
Leaves: Yellow evening primrose leaves are deeply incised and quite long – up to 10 inches in length. The long lance-shaped leaves are in tufts or rosettes, 2-8 inches long, up to ½ inch wide. The lower part of the leaf is deeply cleft or lobed half the distance or more to the middle. The uppermost part is entire to somewhat wavy and toothed.
Stems: Up to 4 inches tall, sparsely covered with minute, straight, stiff hairs, or nearly hairless.
Yellow evening primrose is found in moist areas throughout Utah.
Soils: Moist, well-drained, rocky soils.
Associated Species: Redtop, sedges, willows, rushes
Uses and Management: