Ironweed is an herbaceous native perennial wildflower in the Aster family (Asteraceae) and is found in all areas of NC. It may grow 5 to 8 feet tall and prefers rich moist acidic soils but will grow in average moist to wet soils in full sun. Propagate by seed. The deep purple flowers appear in clusters from mid-summer to mid-fall on strong stems. This low-maintenance wildflower naturalizes easily and is adaptable to garden conditions. This plant was selected as the 2004 NC Wildflower of the Year , a program managed by the North Carolina Botanical Garden with some financial support from the Garden Club of North Carolina. Native bees nest in the dead, hollow stems, so gardeners are encouraged to cut back dead stems to 12 to 24 inches and allow them to remain standing until they disintegrate on their own. Read more about best practices for stem-nesting bees in this NC Extension publication . Use in a rain garden, cottage garden, meadow, along streams or ponds or the back of the border. If a shorter plant is desired, prune it back in spring to about 2 feet. It is attractive if blooming occurs at different heights, so prune to different heights for this effect. Insects, Diseases, and Other Plant Problems: No significant problems
Source: NC State Extension Gardener Plant Toolbox ↗Reconciled to full toolbox: matched by slug to slug 'vernonia-noveboracensis'. Identity (id/common/scientific name) preserved from the original 87-plant Hunnicutt set; attribute data refreshed from the 58-attribute toolbox scrape.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; High Organic Matter; Loam (Silt)
Soil pH
Acid (<6.0)
Soil drainage
Moist | Occasionally Wet
Available space
3 feet-6 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 5 ft. 0 in. - 8 ft. 0 in. | Width: 3 ft. 0 in. - 4 ft. 0 in.
Growth rate
Medium
Maintenance
Low
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Foliage
Deciduous
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Lanceolate
Leaf margin
Serrate
Leaf size
> 6 inches long
Hairs present
Yes
Leaf detail
Alternate, lanceolate and finely toothed with a downy underside and pointed tips. Base is wedge-shaped. 6-8 inches long.
Flower color
Purple/Lavender
Flower value
Good Cut; Showy
Flower form
Cyme
Flower size
< 1 inch
Flower detail
Showy tiny, fluffy, deep purple, disc flowers (no rays) in loose, 3-4 inch wide, terminal clusters. Blooms from July to September
Bloom time
Fall; Summer
Fruit color
Brown/Copper
Fruit type
Achene
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Rusty colored seeds August to October
Stem color
Brown/Copper; Green
Stem detail
Leafy stems green to rusty color are stiff and reach 4'-6'. They may be smooth or have stiff hairs.
Wildlife & Ecology
Native status
Native
Origin
Eastern and southeastern United States
Distribution
AL, CT, DC, DE, FL, GA, KY, MA, MD, NC, NH, NJ, NY, OH, PA, RI, SC, TN, VA, WV
Wildlife value
Flowers are attractive to butterflies, bees and other pollinators. Songbirds eat the seeds. Members of the genus Vernonia support the following specialized bee: Melissodes (Eumelissodes) denticulatus. Dead stems are used by stem-nesting bees.