Siskiyou lewisia Lewisia cotyledon
Siskiyou lewisia (Lewisia cotyledon) is an evergreen perennial flowering plant in the Montiaceae family, native to Siskiyou and Klamath Mountains, Oregon and California (granite and serpentine crevices). It grows 15–30 cm (6–12 in) tall and 20–30 cm (8–12 in) wide, wants part sun to part shade and low water, and is hardy to about -25 °C (-13 °F). Space plants about 25 cm (10 in) apart.
Plan Siskiyou lewisia in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Siskiyou lewisia at a glance
| Type | Perennial flowering plant, evergreen |
|---|---|
| Family | Montiaceae |
| Mature height | 15–30 cm (6–12 in) |
| Mature spread | 20–30 cm (8–12 in) |
| Spacing | 25 cm (10 in) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | Low; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 5–7 |
| Cold hardiness | About -25 °C (-13 °F) once established (roughly USDA zone 5) |
| Heat stress | Likely above about 28 °C (82 °F) |
| Flowering | from about May for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Siskiyou and Klamath Mountains, Oregon and California (granite and serpentine crevices) |
| Common in gardens of | 🇺🇸 United States, 🇬🇧 United Kingdom |
Is Siskiyou lewisia toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
No toxicity reported in ASPCA or standard poison references.
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 Siskiyou lewisia
No well-documented helpful pairing. Group it with plants that like part sun to part shade and low water.
See Siskiyou lewisia in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- Arctic-Alpine Botanic Garden (20 plants)
- Kew: glasshouses and rock garden (7 plants)
Questions about Siskiyou lewisia
- How far apart should I plant Siskiyou lewisia?
- About 25 cm (10 in) apart, centre to centre. A mature plant spreads 20–30 cm (8–12 in).
- Does Siskiyou lewisia need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Siskiyou lewisia need?
- Low water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Siskiyou lewisia?
- It tolerates about -25 °C (-13 °F) once established, roughly USDA zone 5.
- When does Siskiyou lewisia flower?
- From about May for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Siskiyou lewisia 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. No toxicity reported in ASPCA or standard poison references.
- What grows well with Siskiyou lewisia?
- There is no well-documented companion pairing for Siskiyou lewisia. Group it with plants that like the same sun (part sun to part shade) and water (low).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- RHS Plant Finder, Royal Horticultural Society
- USDA PLANTS Database, USDA NRCS
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
Notes and assumptions
- Alpine: needs sharp drainage (scree, gravel or a rock-garden pocket) and resents winter wet more than cold.
- Rots if water sits in the rosette: plant on its side in a vertical crevice, as in the wild. Striped pink, apricot or white flowers.
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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- Zinnia Zinnia elegans
- Cosmos Cosmos bipinnatus
- Purple coneflower Echinacea purpurea
- Foxglove Digitalis purpurea
- Daffodil Narcissus pseudonarcissus