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Vernonia gigantea

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Plant types and subtypes: Perennials

Light Requirements: sun, part-sun, part-shade

Water Use: medium

Soil Moisture: moist

Soil Description: acid, neutral, average, loam, clay

Height: 5'-9'

Bloom Time: July, August, September

Bloom Color: purple, lilac

Leaf Color: green

Hardiness Zone: 5, 6, 7, 8, 9

Additional Tags: attracts bees, attracts butterflies, clumping, colonizing, cut flowers, deer resistant, naturalizing

Vernonia gigantea (giant ironweed)
  • Vernonia gigantea (giant ironweed)
  • Vernonia gigantea (giant ironweed)
  • Vernonia gigantea (giant ironweed)
  • Vernonia gigantea (giant ironweed)

Pricing & Availability

Description

Vernonia gigantea

Also known as:

giant ironweed

,

tall ironweed

Scientific Synonyms:

Description

Vernonia gigantea is the tallest of the ironweeds, and is also the species with the broadest native range. The rigid central stems can grow to a height of 9', or more under certain conditions. These are terminally branched and bear flat clusters of vibrant purple flowers. Although the individual flowers are small (only 1/4" across), they are borne on dense panicles up to 16" across. The alternate leaves are lance-shaped with finely toothed margins, up to 12" long by 2 1/2" wide, the top of which are dark green, whitish and pubescent on the undersides. The seeds are bullet-shaped, connected to small tufts of hair, and are easily distributed by the wind.

Cultivation

Giant ironweed is adaptable to a wide range of light and soil conditions. It tolerates the open shade of forest clearings and margins, as well as the full sun of open prairies and meadows so long as the soil does not dry out for extended periods of time. The root system is fibrous and rhizomatous, and will slowly spread to form dense clumps. The blooming period is long, up to 1 1/2 months, beginning as early as July and extending as late as September. Zones 5-9

Propagation

Can be propagated by root division when dormant. Seed germination rates are low, and those that are self-sown lose viability within 7 months.

Additional Notes

Vernonia gigantea is very attractive to nectaring insects and, given enough space, can be a stunning addition to a pollinator or rain garden. It is not palatable to mammalian browsers, and is highly deer resistant.

Native Range & Classification

Recorded County Distribution: USDA data

Native Range:
AL, AR, DE, FL, GA, IA, IL, IN, KS, KY, LA, MD, MI, MO, MS, NC, NY, OH, OK, PA, SC, TN, TX, VA, WV

USDA Endangered Status:

  • Endangered: NY

Classification

Kingdom Plantae Plants
Subkingdom Tracheobionta Vascular plants
Superdivision Spermatophyta Seed plants
Division Magnoliophyta Flowering plants
Class Magnoliopsida Dicotyledons
Subclass Asteridae
Order Asterales
Family Asteraceae Aster family
Genus Vernonia ironweed
Species Vernonia gigantea giant ironweed