Nodding onion Allium cernuum
Nodding onion (Allium cernuum) is a deciduous perennial flowering plant in the Amaryllidaceae family, native to Most of the United States and southern Canada, from the Appalachians to the Rockies. It grows 30–50 cm (12–20 in) tall and 15–30 cm (6–12 in) wide, wants full sun and low water, and is hardy to about -35 °C (-31 °F). Space plants about 15 cm (6 in) apart.
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Nodding onion at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Amaryllidaceae |
| Mature height | 30–50 cm (12–20 in) |
| Mature spread | 15–30 cm (6–12 in) |
| Spacing | 15 cm (6 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Low; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 5.5–8 |
| Cold hardiness | About -35 °C (-31 °F) once established (roughly USDA zone 3) |
| Heat stress | Likely above about 36 °C (97 °F) |
| Flowering | from about June for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Yes: bulbs and leaves (cooked or raw, onion flavour) |
| Native to | Most of the United States and southern Canada, from the Appalachians to the Rockies |
| Common in gardens of | 🇺🇸 United States, 🇨🇦 Canada, 🇬🇧 United Kingdom, 🇩🇪 Germany |
Is Nodding onion toxic?
- People: not known to be toxic
- Cats: moderately toxic
- Dogs: moderately toxic
- Parts: bulbs, leaves
Like all onions, harmful to cats and dogs (damages red blood cells) if eaten in quantity.
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 Nodding onion
No well-documented helpful pairing. Group it with plants that like full sun and low water.
Keep apart or take care
- caution With Legumes (pea family): Onions, garlic and leeks are said to stunt beans and peas (allium root exudates may reduce nodulation). Traditional companion-planting advice; controlled trials are few, so treat it as a soft preference. Evidence D
- caution With Legumes (pea family): Beans and peas are traditionally kept away from onions, garlic and leeks. Traditional companion-planting advice; controlled trials are few, so treat it as a soft preference. Evidence D
Questions about Nodding onion
- How far apart should I plant Nodding onion?
- About 15 cm (6 in) apart, centre to centre. A mature plant spreads 15–30 cm (6–12 in).
- Does Nodding onion need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Nodding onion need?
- Low water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Nodding onion?
- It tolerates about -35 °C (-31 °F) once established, roughly USDA zone 3.
- When does Nodding onion flower?
- From about June for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Nodding onion poisonous to cats and dogs?
- For cats it is moderately toxic; for dogs moderately toxic; for people not known to be toxic. Like all onions, harmful to cats and dogs (damages red blood cells) if eaten in quantity.
- What grows well with Nodding onion?
- There is no well-documented companion pairing for Nodding onion. Group it with plants that like the same sun (full sun) and water (low).
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
- USDA PLANTS Database, USDA NRCS
Notes and assumptions
- A wild onion whose pink flower clusters hang from a stem bent like a shepherd’s crook in summer; bees love them. Edible like other onions; Chicago is said to take its name from a word for a wild onion or garlic that grew there.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Onion Allium cepa
- Daffodil Narcissus pseudonarcissus
- Garlic Allium sativum
- Leek Allium ampeloprasum (Porrum group)
- Chives Allium schoenoprasum
- Agapanthus Agapanthus praecox
- Ornamental allium Allium giganteum
- Shallot Allium cepa var. aggregatum