Vernonia gigantea Giant Ironweed

Ohio Native Plant Natural Range

To view the natural range of Vernonia gigantea visit the USDA Natural Resources Conservation Service website.
Ironweed seems happy between Cup Plant on the right and Downy Sunflower on the left.

Cultivation Information Giant Ironweed

Bright purple flowers of Giant Ironweed
Height – 7 ftFlower Color – Violet Blooms – Aug - September Sun – Sun to Light Shade Perennial Hardy Zone – 5 to 8PH - 5.0 to 6.0
Soil – Average - Moist Family – Asteraceae
Propagation Notes Giant Ironweed
Seed Stratification
Cold/Moist Storage - 60 days Germination - Best results - We collect our seed and plant it outside in a well-drained flat, protected from heavy rain. Old windows work great! If it is a warm, dry winter, flats will need to be occasionally watered. Viable seed - Start with three or more mature plants. Many times flowers develop in the first season. Collect seed late in the fall once they are brown. Only collect seed when it is dry, never after it has rained. Store in a paper bag, let seed sit for a few weeks, move to a container with a lid. I save different sized containers throughout the year. Collect only what you need - Leaving extra on the plant provides food for birds and other animals. An extra bonus, in the spring you will be rewarded with a generous supply of young New York Ironweed seedlings.
Vernonia gigantea - Roger Dahlin

Wildlife Significance Giant Ironweed

Nectar Source - Butterflies: Eastern Swallowtail and American Lady. Skippers: Crossline, Silver, Fiery, Pecks. Moths: Ironweed Clearwing and Ironweed Borer. Syrphid flies, Soldier Beetles. Numerous native bees, including: Green Sweat bees Bumble bees
Pollen - Long-horned bees (Ironweed specialist)
Birds - Seed
Host Plant - Parthenice Tiger Moth
For details information, visit the Illinois Wildflower website
Giant Ironweed late in the fall by Roger Dahlin
Seed Provenance Giant Ironweed Ironweed
Greene County, Ohio, 2021. Nodding Onion Gardens, 2011 to present. Holden Arboretum, Kirtland, Ohio. Mother plant from a native plant propagation class 2010.
Contact
noddingoniongardens@gmail.com
Location
Columbia Station, Oh 44028 US
Ohio Department of Agriculture Nursery Inspection 2009 - 2026
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