Wild Ageratum; Mist Flower ‘Wild Ageratum or Mist Flower’ Conoclinium coelestinum (Eupatorium coelestinum)

Vigorous perennial bearing fluffy-looking, bluish-purple flowerheads, often occuring in large stands. Resembles the nonnative annual ageratum sold as a bedding plant for flower gardens. That plant, however, is an annual with fibrous roots, while mist flower is a vigorous perennial with a mass of interwoven rhizomes.