The stout stems of Eupatorium (Conoclinum) coelestinum 'Cori' support large clusters of deep periwinkle blue, feathery flowers in early to mid-fall. Eupatorium 'Cori' has light green, crinkly leaves and maroon-green stems. Eupatorium coelestinum spreads aggressively via underground runners. Also known as Hardy Ageratum, it is native from the eastern Great Plains to New York and Florida.
Eupatorium coelstinum 'Cori' prefers full sun and moist to wet soil. Tolerant of coastal conditions and clay soil. Hardy Ageratum is a perennial plant that will self sow in favorable conditions.