Water soldier Stratiotes aloides
Water soldier (Stratiotes aloides) is a deciduous perennial flowering plant in the Hydrocharitaceae family, native to Europe to north-western Asia. It grows 10–30 cm (4–12 in) tall and 30–50 cm (12–20 in) wide, wants full sun and high water, and is hardy to about -28 °C (-18 °F). Space plants about 40 cm (16 in) apart.
Plan Water soldier in your garden →
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Water soldier at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Hydrocharitaceae |
| Mature height | 10–30 cm (4–12 in) |
| Mature spread | 30–50 cm (12–20 in) |
| Spacing | 40 cm (16 in) centre to centre |
| Sun | Full sun, at least 5 h of direct sun a day |
| Water | High; drought tolerance none, waterlogging tolerance high |
| Soil pH | 6.5–8.5 |
| Cold hardiness | About -28 °C (-18 °F) once established (roughly USDA zone 5) |
| Heat stress | Likely above about 28 °C (82 °F) |
| Flowering | from about June for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Low |
| Edible | Not grown as food |
| Native to | Europe to north-western Asia |
| Common in gardens of | 🇬🇧 United Kingdom, 🇮🇪 Ireland, 🇩🇪 Germany, 🇳🇱 Netherlands, 🇵🇱 Poland, 🇸🇪 Sweden, 🇷🇺 Russia, 🇨🇦 Canada |
| Invasive in | Ontario, Canada (Trent River): check local rules before planting |
Is Water soldier toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not poisonous, but the leaf edges are sharply toothed; wear gloves.
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 Water soldier
No well-documented helpful pairing. Group it with plants that like full sun and high water.
Questions about Water soldier
- How far apart should I plant Water soldier?
- About 40 cm (16 in) apart, centre to centre. A mature plant spreads 30–50 cm (12–20 in).
- Does Water soldier need full sun?
- Full sun: at least 5 hours of direct sun a day.
- How much water does Water soldier need?
- High water. Drought tolerance is none and waterlogging tolerance high.
- How cold-hardy is Water soldier?
- It tolerates about -28 °C (-18 °F) once established, roughly USDA zone 5.
- When does Water soldier flower?
- From about June for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Water soldier 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 poisonous, but the leaf edges are sharply toothed; wear gloves.
- What grows well with Water soldier?
- There is no well-documented companion pairing for Water soldier. 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
- Wildflowers and meadows, Plantlife (UK)
- CABI Invasive Species Compendium, CABI
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
Notes and assumptions
- A pond plant: keep it in water all year and plant it in a basket of heavy loam, never rich compost.
- A free-floating rosette like a pineapple top that sinks to the bottom in winter and rises in summer to flower. It shelters pond life, and in the Norfolk Broads it is the breeding plant of the Norfolk hawker dragonfly.
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