Skip to main content
Vernonia noveboracensis (New York Ironweed)
1 / 4
© augochlora, some rights reserved (CC-BY-NC) · iNaturalist
Perennials

Vernonia noveboracensis

New York Ironweed

Asteraceae
Eastern North America — from Massachusetts south to Georgia and west to Mississippi, in moist meadows and streambanks

At a Glance

TypePerennial
HabitUpright
FoliageDeciduous
Height48-72 inches (120-180 cm)
Width24-36 inches (60-90 cm)
Maturity2 years

Growing Zones

USDA Hardiness Zones

4 - 9
Zone 4Zone 5Zone 6Zone 7Zone 8Zone 9
These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →
Frost Tolerancehardy

Key Features

Attracts PollinatorsAttracts ButterfliesAttracts HummingbirdsDeer Resistant
Native to North America
Maintenancelow

Overview

Vernonia noveboracensis is New York ironweed — the native wildflower with the deepest, most saturated purple of any North American species, growing 48–72 inches (120–180 cm) tall and 24–36 inches (60–90 cm) wide. Deep violet-purple flat-topped to domed flower clusters from August through October — the purple is so intense and saturated it appears almost electric, deeper than any aster, coneflower, or other native purple. The 'ironweed' name has two origins: the rust-colored (iron-colored) seed heads that follow the flowers, and the iron-hard tough stems that are nearly impossible to break by hand. The species name 'noveboracensis' means 'of New York'. Moist meadows and streambanks. Tall — may flop in rich soil; pinch back in June to reduce height and increase bushiness. Major late-season pollinator plant — swallowtail butterflies are especially attracted. Hardy to zone 4. Deer avoid the foliage.

Native Range

Vernonia noveboracensis is native to eastern North America — from Massachusetts south to Georgia and west to Mississippi.

Suggested Uses

Used in native meadows, pollinator gardens, and wet-site plantings. The deepest purple native wildflower. Pair with goldenrod (gold + purple = the iconic native fall combination). The ultimate purple for native gardens.

How to Identify

Identified by the deepest, most saturated violet-purple flower clusters of any native wildflower — an almost electric purple intensity — on a tall (48–72 inches / 120–180 cm) plant with iron-hard stems. The unmatched purple depth and the tough stems are the combined signature. Rust-colored seed heads = 'ironweed'.

Appearance

Size & Dimensions

Height4' - 6'
Width/Spread2' - 3'

Reaches mature size in approximately 2 years

Colors

Flower Colors

violet
purple

Foliage Colors

dark green

Fall Foliage Colors

brown

Bloom Information

Bloom Period

~5 weeks
J
F
M
A
M
J
J
A
S
O
N
D
SummerFall
Flowering from August through October, approximately 5 weeks. The deepest native purple.

Detailed Descriptions

Flower Description

Deep violet-purple, in flat-topped to domed clusters — the deepest, most saturated purple of any native wildflower

Foliage Description

Dark green, lance-shaped, toothed

Growing Conditions

Sun Requirements

Full SunPartial Shade
Requires 5-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5(Neutral)
357912
Soil Types
loamclay
Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

1-2 years

Care & Maintenance

Care Guide

Plant in full sun. Moist soil. Pinch back in June if height reduction is needed. Hardy to zone 4. Major pollinator plant.

Pruning

Pinch or cut back by one-third in June to reduce height and increase branching. Cut to ground after frost or in early spring. Leave seed heads for birds.

Pruning Schedule

J
F
M
A
M
J
J
A
S
O
N
D
summerearly spring

Maintenance Level

low

⚠️ Toxicity Warning

Non-toxic