Vernonia lettermanii ‘Iron Butterfly’ 3 stars
Flower Description and Bloom Time
Terminal heads of tufted purple flowers appear in late summer and attract hordes of butterflies, especially monarchs on their southward fall migration. Plants bloomed for at least three weeks starting in August. Plants provide a pop of purple toward the end of the bloom season, for which there are few competitors.
Foliage Interest — Color and Texture
Plant stems are upright with attractive, fine-textured, soft leaves, 2.5 to 3 inches long. Evaluators noted that the fine-textured foliage sets this cultivar apart from other ironweed species.
Habit and Growth Rate Observations
In full sun, evaluators noted that plants grew 24 inches tall and 17 inches wide.
Site Preference — Soil and Light
Full sun, well-drained soil. Drought tolerant once established.
Successes and Possible Drawbacks
Deer and rabbits are seldom troublesome; pests and diseases are few. This plant needs full sun for adequate flowering. At one site, the evaluator noted that the plants were growing in a low-light situation and thus did not perform well. One evaluator noted that plants endured heat and drought and that the flower color was very appealing. Another evaluator recommended cutting plants back in early spring so that the standing seed heads create winter interest.
Notes from Growers/Retailers
This compact cultivar is a natural for native plant gardens, butterfly gardens, cottage gardens and other informal settings. Good companions include Joe Pye weed, native grasses, native asters, helenium, Solidago ‘Fireworks’ and other late-blooming perennials.
Parting “SHOT” — The overall evaluation results were Good. 3 stars
This plant was evaluated from 2011-2014 at three sites in Chicago’s western suburbs.