Ironweed is painting the pastures and by-ways purple these days. And what a color! Whoever dubbed it “liturgical purple” knew what they were talking about! Named for English botanist William Vernon, this member of the aster family often stands seven or more feet tall in wet meadows and along roadsides. Don’t mistake it for Joe-Pye weed, the other tall “purple” composite. Joe-Pye has a rounded inflorescence of pinkish flowers and whorled leaves. Ironweed’s intense purple flowers are arranged in a flat-topped inflorescence atop a stem along which the leaves are arranged alternately.
This particular species, giant ironweed (Vernonia gigantea), is one of two ironweeds that inhabit the Domain and four ironweed species statewide. Each flowering “head” is composed entirely of “disk” flowers – unlike sunflowers or black-eyed-Susans it has no showy ray flowers. Nevertheless, the plant is plenty showy. Vernonia is purported to have medicinal value. Some African species are used regularly to treat fever, headache, joint pain, and diabetes. When I was photographing it, the plant was a-buzz with pollinators. In addition to serving as a nectar and pollen source for numerous flying insects, it is an important food species for a number of butterfly and moth larvae.
Sewanee Herbarium 
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