Description
Mistflower (Conoclinium coelestinum), also known as Blue Mistflower or Wild Ageratum, is a spreading native perennial prized for its clouds of soft, violet-blue flowers that bloom in late summer and fall. Found throughout the eastern and central United States, it typically grows 1 to 3 feet tall and forms dense colonies through creeping rhizomes. The plant has triangular to oval, toothed leaves arranged oppositely along square stems, giving it a slightly mint-like appearance. From August through October, clusters of fluffy, disc-shaped flowers appear at the tips of the stems, resembling a misty haze—hence the name.
Mistflower thrives in full sun to partial shade and prefers moist, well-drained soils, though it can tolerate clay and occasional wetness. It naturally occurs in moist meadows, streambanks, woodland edges, and low-lying fields. Hardy in USDA Zones 5 to 10, it spreads easily and can naturalize quickly in garden settings, making it a great choice for rain gardens, pollinator plantings, and naturalized borders. While its spreading habit makes it an effective groundcover, it may require occasional thinning to prevent overcrowding.
Ecologically, Conoclinium coelestinum is a powerhouse for pollinators. Its late-season blooms provide a valuable nectar source for butterflies, including Monarchs (Danaus plexippus) during migration, as well as native bees, skippers, and flower flies. Although it is not a known larval host plant, it plays an important role in sustaining adult pollinators when other food sources are scarce. The plant also supports ecological diversity by filling in blooming gaps late in the growing season.
