Wild Ageratum Conoclinium coelestinum

Commonly called mistflower, this late summer to fall-blooming herbaceous perennial is native to the Eastern United States. It looks like the annual ageratum and in that regard is sometimes commonly called hardy ageratum. It is a showy native plant that 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 from late summer until frost. It is nectar-rich and pollinators love it.

This plant prefers moist humusy soils that do not dry out in full sun to partial shade areas.  Purplish stems have toothed deltoid leaves. Blueish purple flowers are fluffy, tubular (to 1/ 2” across). Cut back taller plants in spring to prevent flopping. This is a great plant to consider for a wildflower garden or naturalized area, does especially well around pond borders as long as spreading roots will not affect other plants.  It is not recommended for smaller planting areas as it spreads aggressively by its rhizomes and self-seeding. Propagate by clump division in early spring. This plant is moderately resistant to damage from deer. 

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

Quick ID Hints:

• Erect herb with clusters of small heads of tubular flowers
• Flowers bluish-purple
• Leaves opposite, deltoidly ovate, crenately serrate