Conoclinium coelestinum

Common Names

Mistflower, Blue Mistflower, Wild Ageratum, Hardy Ageratum, Blue Boneset

Summary

Blue Mistflower (Conoclinium coelestinum) is a rhizomatous perennial in the Asteraceae native to North America, typically 18–36 inches tall and wide, with erect stems and opposite deltoid-ovate serrate leaves; blue to blue-violet disk flowers, 35–70 per head, form flat-topped clusters that bloom from July to October, attracting butterflies and bees.

Prefers full sun to part shade and moist soils, tolerating a range of soil types; it spreads by rhizomes and self-seeding, and can be aggressive if not contained. It is well suited for wildflower gardens, borders, and meadow plantings or naturalized areas, and can be propagated by root division or seed; seed heads can be cut to prevent reseeding.

Lifecycle

Perennial (short-lived)

Height

2-3 feet

Spread

1.5-3 feet

Hardiness Zones

Zones 5-10

Sunlight Requirements

Ideally full Sun. Tolerates partial sun and partial shade.

Soil Type

Moist, fertile, humus-rich, well-drained loam soil (pH 5.6–7.5, best 6.6–7.5)

Soil Drainage

Moist but well-drained

Soil pH

5.5-7.5

Bloom Color

Blue to blue-violet

Bloom Time

Summer to Fall

Foliage Color

Green, sometimes with a reddish or purple tint along veins and stems.

Leaf Lifecycle

Other (Perennial)

Growth Rate

Fast

Seasons of Interest

Summer and Fall

Propagation Methods

Seeds, Division, Cuttings, Layering

Attracts Wildlife

Attracts bees and butterflies