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Eupatorium coelestinum

Common Name(s):
Blue boneset, Blue mistflower, Hardy ageratum, Mistflower, Wild ageratum
Herbs, Native Plants, Perennials, Wildflowers

Eupatorium coelestinum (Synonym Conoclinium coelestinum), commonly called mistflower, is a late summer to fall-blooming herbaceous perennial that is native to the Eastern United States. It looks like the annual ageratum and in that regard is sometimes commonly called hardy ageratum. But it is perennial and can spread aggressively by rhizomes.

It is a showy native plant which is considered a weed in the coastal plain, growing along roadsides on moist ditch banks. Under cultivation, it becomes a choice perennial with 8 weeks of blue flowers.

Regions:  Mountain, Piedmont, Coastal Plains

Seasons of Interest: 

  Blooms:   Late Summer/Fall           Nut/Fruit/Seed:  Fall

Wildlife Value:  This plant is moderately resistant to damage from deer.  Its flowers are attractive to butterflies, especially smaller species, and other pollinators.  Songbirds eat the seeds.

Insects, Diseases, or Other Plant Problems: This plant has some susceptibility to powdery mildew. Leaf miners and aphids may also visit. Plants tend to flop and may need support. Spreading tendencies must be watched, particularly if planted in the perennial border.

Summer, fall
Sun, part shade
1-3 ft.
Flower Color:
Blue, violet, white
USDA Hardiness Zone 5-10
Mistflower typically grows to 1-2’ tall on downy purplish stems clad with coarsely-toothed, ovate-deltoid leaves (to 3” long). The leaves are opposite and triangular.
The flowers of this member of the aster family lack rays. It has numerous small, fluffy, tubular, blue-purple flowers (to 1/ 2” across) with discoid heads that bloom from July to October in dense flat topped terminal clusters (corymbs).
This plant is easily grown in average, medium to wet, well-drained soils in full sun to part shade. It prefers moist, fertile, humusy soils which do not dry out. Mistflower is a vigorous plant that spreads aggressively by rhizomes and self-seeding. In some areas of the U.S., the species is considered to be a spreading weed. Propagate by clump division in early spring. Plants will grow in wet areas. Taller plants may be cut back in summer to prevent flopping.
Division in spring
Full sun to partial shade
Moist, tolerates poor drainage
Piedmont, Coastal Plain
Eastern USA, North Carolina
Life Cycle:
sun, summer, aggressive, ncemgva2018, blue, white, purple, herb, wildflower, perennial, fall, pollinators, partial shade, butterflies

NCCES plant id: 712

Eupatorium coelestinum Eupatorium coelestinum