Blue mistflower (Conoclinium coelestinum) is a fall-blooming perennial that I have a love-hate relationship with (or perhaps slightly annoyed is more accurate than hate). This aggressively-spreading perennial is fairly shallow-rooted, allowing it to skim across the surface and make a home anywhere it can find a little opening. I spend all spring pulling it out only to fall in love with it again this time of year. The specific species name (coelestinum) refers to the beautiful blue color: sky-blue or heavenly.
Native throughout Georgia, this perennial grows 2-3 feet tall. Stems are often purplish, and the toothed leaves are opposite along the stem. It is a member of the Asteraceae family but it lacks showy ray flowers. Several tiny flowers are clustered together on each flower head, several of which are clustered together in terminal clusters—an arrangement that is perfect for the many species of butterflies that visit it.
Some folks still think of it by its former name: Eupatorium coelestinum. It is very similar looking to all the Eupatorium species as well as to white snakeroot (Ageratina altissima) which is blooming now as well. One of its common names is hardy ageratum, a reference to its resemblance to the annual plant known as ageratum (Ageratum houstonianum). Old-fashioned gardeners knew our native as dependable, and it was a popular passalong plant between friends. This time of year you might find it in ditches near old homes. There is some near me where two country roads meet at a stop sign; it makes me smile every fall to see it there. If you need some—I’ll bet you know a friend willing to share (especially in the spring!).