New York ironweed Vernonia noveboracensis
New York ironweed (Vernonia noveboracensis) is a deciduous perennial flowering plant in the Asteraceae family, native to Wet meadows of the eastern United States. It grows 1.2–2 m (3.9–6.6 ft) tall and 60 cm–1 m (24 in–3.3 ft) wide, wants full sun and high water, and is hardy to about -32 °C (-26 °F). Space plants about 70 cm (28 in) apart.
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New York ironweed at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Asteraceae |
| Mature height | 1.2–2 m (3.9–6.6 ft) |
| Mature spread | 60 cm–1 m (24 in–3.3 ft) |
| Spacing | 70 cm (28 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | High; drought tolerance low, waterlogging tolerance moderate |
| Soil pH | 5–7.5 |
| Cold hardiness | About -32 °C (-26 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 36 °C (97 °F) |
| Flowering | from about August for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Wet meadows of the eastern United States |
| Common in gardens of | 🇺🇸 United States, 🇨🇦 Canada, 🇬🇧 United Kingdom, 🇩🇪 Germany |
Is New York ironweed toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not known to be poisonous; bitter, so livestock avoid it.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with New York ironweed
No well-documented helpful pairing. Group it with plants that like full sun and high water.
Questions about New York ironweed
- How far apart should I plant New York ironweed?
- About 70 cm (28 in) apart, centre to centre. A mature plant spreads 60 cm–1 m (24 in–3.3 ft).
- Does New York ironweed need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does New York ironweed need?
- High water. Drought tolerance is low and waterlogging tolerance moderate.
- How cold-hardy is New York ironweed?
- It tolerates about -32 °C (-26 °F) once established, roughly USDA zone 4.
- When does New York ironweed flower?
- From about August for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is New York ironweed poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not known to be poisonous; bitter, so livestock avoid it.
- What grows well with New York ironweed?
- There is no well-documented companion pairing for New York ironweed. Group it with plants that like the same sun (full sun) and water (high).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
- Illinois Wildflowers (descriptions and insect-visitor records), John Hilty, illinoiswildflowers.info
Notes and assumptions
- Tall, stiff stems topped in late summer with loose clusters of intense royal-purple, fluffy flower heads, a favourite of butterflies and bumblebees. Cut back by half in early summer to keep it shorter.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
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