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Vernonia gigantea (giant ironweed) flowers
Vernonia gigantea (giant ironweed) with Panicum amarum
Vernonia gigantea (giant ironweed) with honeybee
Vernonia gigantea (giant ironweed) in the garden
Vernonia gigantea (giant ironweed) seedheads in the late fall garden

giant ironweed

Vernonia gigantea

Regular price
$3.00
Regular price
Sale price
$3.00
Shipping calculated at checkout.

Seeds ship free with orders over $15.00 to all 50 US states. Seeds ship within 24 hours.

ships spring 2025

PLEASE KNOW: Plants shipped in early spring are likely to arrive dormant.

Ironweed are tall US natives that look quite similar to each other. All bloom late in the season; purple flowers are much loved by pollinators, especially butterflies.

Giant ironweed or tall ironweed is one of the tallest ironweeds, growing up to 10' high! It is exceptionally tough, succeeding on dry, average, moist, or wet soil in full sun or part shade. However, it is happiest and grows tallest on medium soil.

Zones: 5 to 8
Family: Asteraceae
Type: Perennial
Height: 60 to 96 in.
Spread: 36 to 72 in.
Exposure: Full Sun to Part Shade
Soil Conditions: Medium to Wet
Bloom Time: August to September
Bloom Color: purple-violet
Native Range: from Iowa and Kansas south to Texas and east to New York south to Florida with the exception New Jersey

Special Characteristics
  • Pollinator favorite
  • Little to no care required (once established)
  • Architectural
image credits

Ali McEnhill, The Old Dairy Nursery

Vernonia gigantea (giant ironweed) flowers
Vernonia gigantea (giant ironweed) with Panicum amarum
Vernonia gigantea (giant ironweed) with honeybee
Vernonia gigantea (giant ironweed) in the garden
Vernonia gigantea (giant ironweed) seedheads in the late fall garden

Ordering information

Preorders

You may place your order anytime to reserve plants for spring 2025 shipment. If you place multiple orders, we will combine plants into one box (or as many as needed) and any extra shipping charges will be refunded when we ship.

We will begin shipping plants as soon as plants begin to emerge from dormancy in spring. Woodies will likely begin shipping in April. Perennials will likely begin shipping in May. If ordering multiple varieties, we will hold until all plants are ready to ship together. If you would like to receive plants sooner please reach out.

We will check in with you a week before shipping to make sure you receive your plants at a time that is convenient for you.

Shipping

Live plants ship in spring and fall only. Plants may ship dormant, depending on variety and season. Shipping costs are most reasonable when bundling like size plants.

  • 4-inch: 1-6 plants ship for $15.00 / 7-13 plants ship for $18.00 / 14-30 plants ship for $40.00
  • 1-gal: 1-2 plants ship for $18.00 / 3-4 plants ship for $25.00 / 5-6 plants ship for $40.00
  • trees & shrubs: $27.00-$40.00 each, height dependent
  • seeds: $6.75 or free with orders over $15.00

We regret that we cannot ship internationally or to the following states: AK, AZ, CA, CO, FL, HI, ID, MT, NV, OR, UT, or WA.

Read more about our shipping policies here.

Nursery pick up

Plants can be collected from the nursery Monday through Sunday from 10am-4pm in Spring, Summer, and Fall. We prefer 24 hour notice to get your order together and will email you when ready for collection.

If you place a SPRING 2025 PREORDER, we will contact you in spring when your plants are ready for collection. Woodies will likely become available for collection in April. Perennials will likely become available in May. If ordering multiple varieties, we will hold until all plants are ready to be collected together.

Plant Sizes

We most commonly use the following pot sizes for perennials:

  • 4-inch pot: 3.5" H x 3.5" W x 3.5" D
  • 2-quart pot: 6" H x 5.25" W x 5.25" D
  • 1-gallon pot: 6.87" H x 8" Dia (this is a true one gallon pot, not the smaller 'trade' one gallon pot used by many nurseries)

Check out our illustrated pot size guide here.

Representative trees & shrubs are photographed in their pots and posted on each plant page.

Sustainability

Sustainability is at the heart of what we do at The Old Dairy. We grow all of our plants outdoors without the use of chemicals, fertilizers, carbon fuels, or peat.

Many of our perennials are grown in the ground and dug upon order (this is especially true for larger sizes). This practice allows us to grow stronger, healthier plants using native soil, and ultimately reduces our impact on the environment.

Our open-pollinated seeds are collected from plants in our mother beds, which have never been treated with chemicals or sprays of any kind.

Read all about our sustainable practices here.

Germination information

Sowing Instructions

This plant is generally easy to grow from seed, however, germination can be erratic. Do not discard seed tray too early. Fall sowing strongly recommended.

Sow thinly on a high quality seed starting mix and cover lightly. Seeds should be kept consistently moist, though not wet. Please do not use a humidity dome. Bottom watering is best. Temperatures under 41 degrees can be very effective. Do not leave in direct sunlight.

Timing Options

Fall · Outdoors · We prefer to grow according to the natural rhythms of the season. We sow most of our seed in late summer or fall. They germinate in warm daytime temperatures, sleep through winter, then reemerge in spring.


Spring · Outdoors · 
Seed can be started outdoors when temperatures warm in spring. Wait until daytime temperatures are consistently in the mid to high 60s.


Late Winter · Indoors · 
Seed can be started indoors under lights 6-8 weeks before your last frost date. Plants may germinate faster this way, but they will be less robust. We strongly recommend sowing outdoors according to the natural rhythms of the season

Looking for more detail?

garden location coming soongarden location coming soon
Vernonia gigantea (giant ironweed) with Panicum amarumVernonia gigantea (giant ironweed) with Panicum amarum

view this plant in our gardens:

Vernonia gigantea | Nursery: Greenhouse Garden 2024

seedling image

Vernonia gigantea

We are slowly creating a seedling image library to help make weeding easier.
Vernonia gigantea (giant ironweed) with Panicum amarumVernonia gigantea (giant ironweed) with Panicum amarum
garden location coming soongarden location coming soon