Narrow-leaf or Letterman's ironweed is an upright, clump-forming, herbaceous perennial native to rocky outcrops, floodplains, and river scours in west-central Arkansas and adjacent areas of Oklahoma. Plants can reach around 2' tall with an equal spread. The finely textured leaves are thin and narrow. Flat-topped inflorescences of bright purple flowers appear in mid to late summer. Highly attractive to hummingbirds, butterflies, and other pollinators. Easily grown in medium to dry, well-draining soils of average fertility in full sun. Tolerant of various soil conditions, including hot, dry, rocky, and alkaline. Also tolerant of occasional flooding and drought once established. A rugged perennial for fine texture in pollinator gardens, native plantings, slopes, rock gardens, and xeriscapes. 'Iron Butterfly' is a vigorous cultivar selected for its compact, densely mounding habit and showy, long-lasting display of purple blooms.

Exposure: Sun
Soil: Dry to medium moisture; tolerates drought, erosion, dry, shallow-rocky
Hardiness: USDA Zones 4-9