Tall Ironweed, Vernonia altissima

Tall Ironweed

Vernonia altissima

Benefits: Pollinator Benefit Graphic
Sun Shade: Plant Light Requirements Graphic
Bloom Time: Late Summer/Early Fall
Hardiness Zones: 4, 5, 6, 7, 8, 9
Soil Conditions: Clay, Loam, Sand
Soil Moisture: Moist, Wet
Color: Purple, Red
Fragrance: No
Height: 5-8 feet
Spacing: 2 feet

Tall Ironweed (Vernonia altissima) or Giant Ironweed has showy bright magenta flowers that bloom in late summer to early fall. It is a great way to attract pollinators because it serves as a late-season nectar source. This is an upright perennial that typically grows 5-8 feet in cultivation on stiff, leafy stems which branch at the top. Lanceolate to lanceolate-ovate leaves (to 10 inches long) have irregularly serrated margins. Composite flowers, each with dense, fluffy, rose-purple disks (rays absent), bloom in corymbose cymes.

The blooming period occurs from late summer to early fall and lasts about 1–1½ months. Each disk floret is replaced by a small achene that is gray or brown and bullet-shaped; the apex of each achene has a small tuft of both short and long hair hairs (or bristles) that are pale purple to tawny. These achenes are distributed by the wind. The root system consists of short thick rhizomes with fibrous roots below. Small clumps of plants are produced from the rhizomes.

Habitats include open woodlands, woodland borders, thickets, areas along woodland paths, swamps, riverbottom prairies, seeps and springs, pastures, and abandoned fields. In woodlands, this plant requires occasional disturbance to prevent excessive shade from neighboring trees.

The preference is full sun to light shade, moist to mesic conditions, and soil containing loam, clay-loam, silt-loam, or sandy loam. Plants growing in sunny areas require more moisture than those growing in the shade.

This plant spreads by rhizomes to form clumps. Because it can spread aggressively, Tall Ironweed is often categorized as a common pasture weed. It will readily self-hybridize with other Ironweed species which can make plant ID difficult in the field.

 Plant Notes and Herbal Uses
  Ironweeds is bitter to the taste, so herbivorous animals like deer and cattle will avoid consuming it.
 Further Information

 Wisconsin Fruit Trees
 Wisconsin Edible Berry Shrubs
 Widsconsin Edible Plants-Eat On The Wild Side
 8 Dandelion Recipes
 Wisconsin Native Plant Nurseries

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