Cape pondweed (water hawthorn, waterblommetjie) Aponogeton distachyos
Cape pondweed (water hawthorn, waterblommetjie) (Aponogeton distachyos) is a deciduous perennial flowering plant in the Aponogetonaceae family, native to Western Cape, South Africa. It grows 5–10 cm (2–4 in) tall and 60 cm–1.2 m (24 in–3.9 ft) wide, wants part sun to part shade and high water, and is hardy to about -12 °C (10 °F). Space plants about 60 cm (24 in) apart.
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Cape pondweed (water hawthorn, waterblommetjie) at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Aponogetonaceae |
| Mature height | 5–10 cm (2–4 in) |
| Mature spread | 60 cm–1.2 m (24 in–3.9 ft) |
| Spacing | 60 cm (24 in) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | High; drought tolerance low, waterlogging tolerance high |
| Soil pH | 6–8 |
| Cold hardiness | About -12 °C (10 °F) once established (roughly USDA zone 8) |
| Heat stress | Likely above about 30 °C (86 °F) |
| Flowering | from about March for 17–29 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Yes: flower buds and flowers |
| Native to | Western Cape, South Africa |
| Common in gardens of | 🇿🇦 South Africa, 🇬🇧 United Kingdom, 🇮🇪 Ireland, 🇫🇷 France, 🇦🇺 Australia, 🇳🇿 New Zealand, 🇺🇸 United States, 🇨🇱 Chile |
| Invasive in | south-eastern Australia (naturalised in waterways): check local rules before planting |
Is Cape pondweed (water hawthorn, waterblommetjie) toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not poisonous; the flowers are eaten as a vegetable in South Africa.
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 Cape pondweed (water hawthorn, waterblommetjie)
No well-documented helpful pairing. Group it with plants that like part sun to part shade and high water.
Questions about Cape pondweed (water hawthorn, waterblommetjie)
- How far apart should I plant Cape pondweed (water hawthorn, waterblommetjie)?
- About 60 cm (24 in) apart, centre to centre. A mature plant spreads 60 cm–1.2 m (24 in–3.9 ft).
- Does Cape pondweed (water hawthorn, waterblommetjie) need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Cape pondweed (water hawthorn, waterblommetjie) need?
- High water. Drought tolerance is low and waterlogging tolerance high.
- How cold-hardy is Cape pondweed (water hawthorn, waterblommetjie)?
- It tolerates about -12 °C (10 °F) once established, roughly USDA zone 8.
- When does Cape pondweed (water hawthorn, waterblommetjie) flower?
- From about March for 17–29 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Cape pondweed (water hawthorn, waterblommetjie) 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; the flowers are eaten as a vegetable in South Africa.
- What grows well with Cape pondweed (water hawthorn, waterblommetjie)?
- There is no well-documented companion pairing for Cape pondweed (water hawthorn, waterblommetjie). Group it with plants that like the same sun (part sun to part shade) and water (high).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- PlantZAfrica, South African National Biodiversity Institute
- 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.
- Oblong floating leaves and forked white flower spikes with a strong vanilla scent, in the cool months; it rests in summer heat. In the Cape the flowers are stewed with mutton in waterblommetjiebredie.
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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