Western red cedar Thuja plicata
Western red cedar (Thuja plicata) is an evergreen perennial tree in the Cupressaceae family, native to Pacific Northwest (moist lowland and coastal forest). It grows 25–50 m (82–164 ft) tall and 8–14 m (26–46 ft) wide, wants part sun to part shade and high water, and is hardy to about -30 °C (-22 °F). Space plants about 8 m (26 ft) apart.
Plan Western red cedar in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Western red cedar at a glance
| Type | Perennial tree, evergreen |
|---|---|
| Family | Cupressaceae |
| Mature height | 25–50 m (82–164 ft) |
| Mature spread | 8–14 m (26–46 ft) |
| Spacing | 8 m (26 ft) centre to centre |
| Sun | Part sun to part shade, at least 3 h of direct sun a day |
| Water | High; drought tolerance low, waterlogging tolerance moderate |
| Soil pH | 5–7.5 |
| Cold hardiness | About -30 °C (-22 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 34 °C (93 °F) |
| Wind tolerance | Moderate |
| Pollinator value | None |
| Edible | Not grown as food |
| Native to | Pacific Northwest (moist lowland and coastal forest) |
| Common in gardens of | 🇺🇸 United States, 🇬🇧 United Kingdom |
Is Western red cedar toxic?
- People: mildly toxic
- Cats: mildly toxic
- Dogs: mildly toxic
- Parts: foliage
Thujone oils; stomach upset if chewed.
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 Western red cedar
No well-documented helpful pairing. Group it with plants that like part sun to part shade and high water.
See Western red cedar in a botanical garden
It grows in this sample garden, which you can walk through in 3D:
- The Butchart Gardens (3 plants)
Questions about Western red cedar
- How far apart should I plant Western red cedar?
- About 8 m (26 ft) apart, centre to centre. A mature plant spreads 8–14 m (26–46 ft).
- Does Western red cedar need full sun?
- Part sun to part shade: at least 3 hours of direct sun a day.
- How much water does Western red cedar need?
- High water. Drought tolerance is low and waterlogging tolerance moderate.
- How cold-hardy is Western red cedar?
- It tolerates about -30 °C (-22 °F) once established, roughly USDA zone 4.
- Is Western red cedar poisonous to cats and dogs?
- For cats it is mildly toxic; for dogs mildly toxic; for people mildly toxic. Thujone oils; stomach upset if chewed.
- What grows well with Western red cedar?
- There is no well-documented companion pairing for Western red cedar. 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).
- USDA PLANTS Database, USDA NRCS
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
Notes and assumptions
- Buttressed, fibrous-barked giant; the "tree of life" of Northwest Coast peoples (canoes, totem poles, longhouses).
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
- Creeping juniper Juniperus horizontalis
- Leyland cypress x Cuprocyparis leylandii
- Hinoki cypress Chamaecyparis obtusa
- Dawn redwood Metasequoia glyptostroboides
- Bald cypress Taxodium distichum
- Eastern red cedar Juniperus virginiana
- Northern white cedar (arborvitae) Thuja occidentalis
- Common juniper Juniperus communis