Sundrops
Sundrops are 8 to 24" in height, and grow a single stalk or a stalk with a few branches. The flowers are yellow and similar to Evening Primrose, blooming early to mid-summer and lasting about a month. The flowers open during the day and close at night, the opposite of Evening Primrose. These plants like full to part sun, moist to dry, well-draining soil with sand or gravel. They like sandy meadows or dappled shade, and may eventually get shaded out by trees or taller vegetation unless fire or other means keeps their habitat open.
Members of the Oenothera family support a specialist bee, Lasioglossum oenotherae, according to IllinoisWildflowers.net. The flowers are also visited by other bees, skippers, and butterflies, while Wood Nymphs, Primrose Moths, Momphid Moths, and other insects feed on various parts of the plant. In turn, the insect life supports birds, and some also feed on the seeds in fall.
Naturalizes into meadows, forest edges, or along lakeshores, but does well in a garden setting as a border or in a rock garden. Great for the front of pollinator or butterfly gardens.