838 Conoclinium coelestinumCommon Names: mistflower, blue mistflower, wild ageratum, pink eupatorium, hardy ageratum, blue boneset Family: Asteraceae (aster/daisy Family)
Mistflower has a flower color that is almost unique. The flowers of chicory and flossflower (Ageratum houstonianum) come close. Photographic film just doesn't get it, and so we use a digital image here. The color has been described as clear blue, powder blue, azure blue, bluish-purple, reddish-purple, blue-pinkish, and pink-purplish. I have always called it "sky-blue pink." A stand of mistflower in bloom will rock your eye balls! Mistflower is a herbaceous perennial which spreads by creeping rhizomes and covers the ground with a mat of opposite, wrinkled, coarsely toothed, triangular leaves 1-3 in (2.5-7.6 cm) long on short petioles. In autumn mistflower produces branched stems 1-2 ft (0.3-0.6 m) tall that bear dense, flat clusters, 2-4 in (5-10 cm) across, of irregular fuzzy flowerheads - 30-70 flowerheads per cluster. There are no ray flowers, only disk flowers, and it's their long stamens that cause the fuzzy appearance. A handful of cultivars have been selected. 'Wayside Form' is compact and only 15 in (38 cm) tall. 'Album' has white flowers - what's the point?
Mistflower, Conoclinium coelestinume,occurs in floodplains, along pond and stream margins, in fields and wet meadows and along road shoulders from New Jersey, west to Wisconsin and Kansas, and south to Texas and Florida.
CultureMistflower is easy to grow and is capable of overstepping its bounds by producing abundant seeds dispersed by wind and spreading by long, underground rhizomes. Cut back in early summer to increase branching and produce more flowers, but don't make the mistake I did and mow in August - my mistflowers were very resentful and refused to bloom that year. Light: Full sun to partial shade. Moisture: Mistflower likes plenty of water. It will survive in dry soils without supplemental watering, but it will be shorter, flowering will not be as grandiose, and it will not spread as much as plants that get regular irrigation. Hardiness: USDA Zones 4 - 11. Propagation: You won't have any trouble propagating mistflower. Sow seeds in autumn or divide the root clumps and rhizomes in spring.
Mistflower is best used in wildflower gardens where it may naturalize freely. It's great for use on the edges of ponds and water gardens. Mistflower is used in perennial borders, too, but it can become overplentiful if not kept under control. Better to keep it away from your favorite, less robust perennials. Mistflower can tolerate partial shade and is useful on the edges of the woodland garden. Grown in drier soils and partial shade, mistflower is not at all invasive. The unusual color makes mistflower a great additions to floral arrangements. Butterflies sip nectar from the flowers.
The dense flower clusters of the perennial mistflower are almost identical to those of the tropical annual, flossflower (also known as ageratum), but the latter doesn't have rhizomes. Mistflower is a welcome flower late in autumn when many perennials have faded to memory.
Mistflower can become invasive in and near gardens.
Steve Christman 10/24/00; updated 10/6/03