Conoclinum (Eupatorium) coelestinum – Blue Mistflower

General Information: Numerous blue-ish purple fluffy discs, each about 1/2″ across, adorn the tops of the stems of this native perennial. The leaves of Blue Mistflower emerge in spring, followed by flowers from July through October. Each flower consists of disc florets without rays, creating the namesake misty appearance of each flower head. After flowering, the numerous seeds this plant produces are dispersed by birds and the wind. During the summer, the abundant nectar produced by the aggregations of tiny flowers attracts various Bees, Butterflies, and Moths. During the winter, the seed heads attract songbirds. Blue Mistflower is a wonderful perennial that is well-suited for replacing similar annual species, affording growers a much more effective means of enjoying the heavenly blue beauty of these gorgeous flowers. This plant has been used medicinally by Indigenous Peoples throughout the plant’s native range. The genus ‘coelestinum’ translates to ‘heavenly’ or ‘celestial’. The flat-top clusters attract nectar-loving insects. A nectar source and host species for several types of moths.

Cultivation Details: Blue Mistflower spreads laterally at the root by rhizome. Rhizome divisions can be made in late spring if mass plantings are desired. The plants are also known to self-seed and can quickly spread in favorable conditions such as moist bottomlands and woodland edges. The spread of these plants can be controlled by rhizome pruning and deadheading flowers before they go to seed. The top 1/3 of the plants can be cut in the summer before the flower buds form to allow for a the floral display of blossoms to be smaller in stature. Can be used in mass plantings to naturalize due to the ease with which they can spread. Consider pairing with yellow flowers for contrast. See our “Attracts Wildlife” category for other plants to pair with. Ideal for filling in moist areas, as a (usually) tall groundcover under moisture-loving trees and shrubs, for woodland gardens, border plantings, wet meadows, native plant gardens, pollinator gardens, or as a specimen. Will tolerate disturbed areas as long as it is moist.

Growing Requirements: Plant in full to part sun. Plants grown in full sun and in slightly drier conditions may spread less than those in partial shade, although their overall vigor may also be impacted. Prefers moist, well-drained, humus-rich soils. Tolerates sandy or clay soils if amended with organic matter. Suitable for mildly acidic, neutral, and mildly alkaline soils.

Fun Facts: This plant is sometimes called “Wild Ageratum” due to the floral resemblance these plants have. Unlike the cultivated Ageratum, however, Blue Mistflower is a perennial and native to the US. Originally, Linnaeus assigned it to the genus Eupatorium, along with bonesets, blue mistflower is sometimes still referred to as blue boneset.