perennialN. America Native

Broadleaf Ironweed

The Story

Plant Bio

Vernonia glauca is an upright, clump-forming herbaceous perennial native to eastern North America, reaching three to five feet in height on rigid, self-supporting stems. Its simple, lance-shaped foliage is dark green on top with a distinct whitish, glaucous underside.

Unlike wetland-dwelling ironweeds, broadleaf ironweed thrives in dry to medium-moist, well-drained soils with notable drought resistance. Late summer blooms consist of broad, flat-topped terminal clusters of deep royal purple disc florets that lack ray petals entirely.

Uses & Benefits:

Deep royal purple bloom clusters stand tall in late summer borders atop stiff, architectural stems.

High drought tolerance and adaptability to varied soil pH make it reliable for low-water landscapes.

Nectar sources feed butterflies, bees, and hummingbirds, while winter stems shelter native stem-nesting bees.

Essentials

At a Glance

Plant Type

Perennial

Height

59"

Width

47"

Light

Full Sun, Partial Sun

Zones

6, 7, 8

Water

Low to medium

Humidity

Tolerates high summer heat and humidity

Lifespan

Perennial

Native To

Eastern North America

Toxicity

Non-toxic

Bloom period

Late summer – Early fall

In flower about 2 months of the year

Planting

How to Grow

Choose a site receiving at least six hours of direct full sun daily in well-draining soil.
Dig a hole twice as wide as the root ball and level with the existing container depth.
Backfill with native soil, firming lightly around the crown, and water thoroughly to settle.
Mulch the root zone with two inches of organic matter, keeping mulch clear of main stems.

Pro Tip

Pinch stem tips back by half in late spring to reduce mature height and stimulate branching, and leave twelve to twenty-four inches of standing stem stubble during winter cleanup to provide nesting sites for stem-nesting bees.

Keep It Thriving

Care Guide

Do

Provide well-drained soil to protect roots from winter waterlogging.
Leave hollow dead stems standing through winter for wildlife shelter.

Don't

Do not plant in soggy, poorly drained sites or waterlogged clay beds.
Do not prune dead stems down to ground level in fall if supporting native stem-nesting bees.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Pest Check
Pinch
Propagate
Spring Cleanup

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Pollinator GardenNative Plant MeadowPerennial BorderRain-Adjacent Buffer

Companion Plants

Liatris spicata Echinacea purpurea Solidago speciosa Monarda fistulosa

Multiply

Propagation Methods

Good to Know

Common Questions

Broadleaf Ironweed questions

What zones can Broadleaf Ironweed grow in?

Broadleaf Ironweed is hardy in USDA Zones 6–8. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Broadleaf Ironweed deer resistant?

Yes — Broadleaf Ironweed is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Broadleaf Ironweed bloom?

Broadleaf Ironweed typically blooms in late summer through early fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Broadleaf Ironweed need full sun?

Broadleaf Ironweed does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Broadleaf Ironweed drought tolerant?

Yes — once established (usually after the first full season), Broadleaf Ironweed handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.