Conoclinium

Conoclinium, the mistflowers, is a genus of four species of herbaceous perennial flowering plants, native to North America. They are 0.5 to 2 metres (1.6 to 6.6 ft) tall, and have blue to purple or violet flowers (occasionally white). The plants of this genus have sometimes been classified in the genus Eupatorium, but late 20th century research shows they are more closely related to other plants of the Eupatorieae, such as Ageratum. The generic name is derived from the Greek words κῶνος (kônos), meaning "cone", and κλινίον (kliníon), meaning "little bed"....read more on Wikipedia.