Flowering rush Butomus umbellatus
Flowering rush (Butomus umbellatus) is a deciduous perennial flowering plant in the Butomaceae family, native to Europe and temperate Asia. It grows 60 cm–1.3 m (24 in–4.3 ft) tall and 40–60 cm (16–24 in) wide, wants full sun and high water, and is hardy to about -30 °C (-22 °F). Space plants about 45 cm (18 in) apart.
Plan Flowering rush in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Flowering rush at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Butomaceae |
| Mature height | 60 cm–1.3 m (24 in–4.3 ft) |
| Mature spread | 40–60 cm (16–24 in) |
| Spacing | 45 cm (18 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | High; drought tolerance none, waterlogging tolerance high |
| Soil pH | 6–8 |
| Cold hardiness | About -30 °C (-22 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 32 °C (90 °F) |
| Flowering | from about June for 5–9 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Europe and temperate Asia |
| Common in gardens of | 🇬🇧 United Kingdom, 🇮🇪 Ireland, 🇫🇷 France, 🇩🇪 Germany, 🇳🇱 Netherlands, 🇵🇱 Poland, 🇷🇺 Russia, 🇹🇷 Turkey, 🇨🇳 China, 🇺🇸 United States, 🇨🇦 Canada |
| Invasive in | USA and Canada (Great Lakes, Pacific Northwest): check local rules before planting |
Is Flowering rush toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not known to be poisonous; the starchy rhizomes have been eaten in parts of Russia and Asia.
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 Flowering rush
No well-documented helpful pairing. Group it with plants that like full sun and high water.
Questions about Flowering rush
- How far apart should I plant Flowering rush?
- About 45 cm (18 in) apart, centre to centre. A mature plant spreads 40–60 cm (16–24 in).
- Does Flowering rush need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Flowering rush need?
- High water. Drought tolerance is none and waterlogging tolerance high.
- How cold-hardy is Flowering rush?
- It tolerates about -30 °C (-22 °F) once established, roughly USDA zone 4.
- When does Flowering rush flower?
- From about June for 5–9 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Flowering rush 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; the starchy rhizomes have been eaten in parts of Russia and Asia.
- What grows well with Flowering rush?
- There is no well-documented companion pairing for Flowering rush. 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
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
- Wildflowers and meadows, Plantlife (UK)
- CABI Invasive Species Compendium, CABI
Notes and assumptions
- A marginal: it stands in shallow water at the edge of a pond or in wet mud; divide clumps every few years.
- Not a true rush: rounded umbels of three-petalled pink flowers on tall stems above sword-shaped, three-angled leaves. The only species in its family.
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
- Sunflower Helianthus annuus
- French marigold Tagetes patula
- English lavender Lavandula angustifolia
- Zinnia Zinnia elegans
- Cosmos Cosmos bipinnatus
- Purple coneflower Echinacea purpurea
- Foxglove Digitalis purpurea
- Daffodil Narcissus pseudonarcissus