Drum roll — or do we even need one to herald the arrival of the late summer/fall wildflowers and their most celebrated members, the Aster Family! Goldenrods and sunflowers have been blooming for weeks; trilobed Rudbeckia arrived on the scene a couple of weeks ago. And now it’s time for the ironweeds — Vernonias — to show their stuff. “Liturgical purple” is how someone has described the color — and it’s spot on! If you tend to confuse this plant with Joe-Pye weed, don’t. Not only is the flower color entirely different, but the structure of the plant and of the head is nothing like that if ironweed.
This is Vernonia gigantea, giant ironweed. Its cousin V. flaccidifolia (Tennessee ironweed), whose spent blossoms are khaki in color, bloomed a few weeks ago on the lower slopes of the plateau. Giant ironweed, splashing its dark purple over upland meadows, waste places, and roadsides, has darker pappus (remains of spent blossoms). And to discriminate between ironweeds and Joe-Pye weed? Check out the arrangement of the leaves. Joe-Pye’s leaves are arranged in whorls, several leaves emerging from the same node. ironweed’s leaf arrangement is alternate. Joe-Pye’s pinkish flowers are arranged in almost a cylinder, whereas those of ironweed form a relatively flat-topped inflorescence.
This plant caught my eye on the side of the highway where a number of us had gathered for the groundbreaking for the Mountain Goat Trail that will stretch, in this second phase, from Sewanee to Monteagle. Soon we’ll be biking past these beauties!