Conoclinium coelestinum

Blue Mistflower, Hardy Ageratum, Blue Boneset

Blue Mistflower is a shrub-like herbaceous perennial native to the south-central and eastern portions the U.S. In NC, is is present in most non-mountainous counties. Growing two to three feet tall and as wide, it has opposite, triangular-shaped leaves and masses of tiny, whimsical, fluffy, bright blue-purple disc flowers in clusters, totally lacking in ray flowers. It stays in bloom through most of the hottest part of summer and well into fall. Blue Mistflower spreads by rhizomes and can be aggressive in the right (or wrong) growing conditions. It should be divided in early spring to control its spread if grown in a perennial border, but it can be allowed to spead as a groundcover in a less controlled siting. It grows well in full sun, with sufficient moisture, but in our experience it tends to stay in bloom longer if given partial shade. Formerly called Eupatorium coelestinum.