Japanese primrose (kurinsō) Primula japonica
Japanese primrose (kurinsō) (Primula japonica) is a deciduous perennial flowering plant in the Primulaceae family, native to Japan. It grows 30–60 cm (12–24 in) tall and 30–45 cm (12–18 in) wide, wants part sun to part shade and high water, and is hardy to about -29 °C (-20 °F). Space plants about 30 cm (12 in) apart.
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Japanese primrose (kurinsō) at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Primulaceae |
| Mature height | 30–60 cm (12–24 in) |
| Mature spread | 30–45 cm (12–18 in) |
| Spacing | 30 cm (12 in) centre to centre |
| Sun | Part sun to part shade, at least 3 h of direct sun a day |
| Water | High; drought tolerance none, waterlogging tolerance high |
| Soil pH | 5–7 |
| Cold hardiness | About -29 °C (-20 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 28 °C (82 °F) |
| Flowering | from about May for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Japan |
| Common in gardens of | 🇯🇵 Japan, 🇬🇧 United Kingdom, 🇺🇸 United States, 🇮🇪 Ireland, 🇩🇪 Germany, 🇳🇱 Netherlands, 🇳🇿 New Zealand |
Is Japanese primrose (kurinsō) toxic?
- People: mildly toxic
- Cats: mildly toxic
- Dogs: mildly toxic
- Parts: leaves, sap
Primulas can cause skin rashes in sensitive people and mild stomach upset in pets (ASPCA lists primrose).
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 Japanese primrose (kurinsō)
No well-documented helpful pairing. Group it with plants that like part sun to part shade and high water.
Questions about Japanese primrose (kurinsō)
- How far apart should I plant Japanese primrose (kurinsō)?
- About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–45 cm (12–18 in).
- Does Japanese primrose (kurinsō) need full sun?
- Part sun to part shade: at least 3 hours of direct sun a day.
- How much water does Japanese primrose (kurinsō) need?
- High water. Drought tolerance is none and waterlogging tolerance high.
- How cold-hardy is Japanese primrose (kurinsō)?
- It tolerates about -29 °C (-20 °F) once established, roughly USDA zone 4.
- When does Japanese primrose (kurinsō) flower?
- From about May for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Japanese primrose (kurinsō) poisonous to cats and dogs?
- For cats it is mildly toxic; for dogs mildly toxic; for people mildly toxic. Primulas can cause skin rashes in sensitive people and mild stomach upset in pets (ASPCA lists primrose).
- What grows well with Japanese primrose (kurinsō)?
- There is no well-documented companion pairing for Japanese primrose (kurinsō). Group it with plants that like the same sun (part sun to part shade) and water (high).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- RHS Plant Finder, Royal Horticultural Society
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
Notes and assumptions
- A candelabra primula: tiers of magenta, pink or white whorls up a tall stem in early summer; seeds itself along streams and boggy ground.
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
- Primrose Primula vulgaris
- Ivy-leaved cyclamen Cyclamen hederifolium
- Creeping Jenny Lysimachia nummularia
- Auricula Primula auricula
- Cowslip Primula veris
- Giant Himalayan cowslip Primula florindae
- Florist’s cyclamen Cyclamen persicum
- Coral ardisia (manryō) Ardisia crenata