Pacific rhododendron
Rhododendron macrophyllum · Ericaceae
Pacific rhododendron (Rhododendron macrophyllum) is a perennial shrub in the Ericaceae family. It is native to North America. USDA records it as hardy in zone 7 and warmer, down to about 7°F.
At a glance
| Type | shrub Derived |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 15 ft USDA |
| Light | part-shade USDA |
| Water need | high USDA |
| Growth rate | moderate USDA |
| Soil pH | 5.5–7 USDA |
| Bloom | March–May USDA |
| Flower color | Purple USDA |
| Hardiness zones | 7 and warmer USDA |
| Guild layer | shrub Derived |
| Nursery availability | Routinely Available USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It grows in partial shade. USDA rates it as having needs consistently moist ground. Its drought tolerance is rated none — it needs reliable moisture. It will not tolerate waterlogged soil — USDA rates its anaerobic tolerance as none. It is recorded on soils from pH 5.5 to 7 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 7.
Size and growth
At maturity it reaches about 15 ft, making it a small tree or large shrub. It grows at a moderate rate.
Bloom period
USDA records a bloom period of March through May. Flowers are purple.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is dark green, coarse in texture. Its flowers are conspicuous. Its fruit or seed heads are conspicuous, extending interest past flowering. Its active growth period is spring and summer. Its winter foliage is dense, which makes it useful for year-round screening. USDA rates its lifespan as moderate.
What the site needs to provide
USDA records it across sites receiving 55 to 125 inches of annual precipitation. It needs at least 270 frost-free days to finish its season. It roots to at least 12 inches. Fertility requirement: medium.
Propagating it
It takes readily from seed, cuttings, bare root and container stock. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a rapid rate. It does not spread vegetatively, so it will stay where you put it.
Resilience and wildlife
Browsing animals rate it barely palatable — the sourced basis for calling it deer-resistant. Its fire tolerance is rated medium. Its growth form is recorded as multiple stem.
Role in a guild
Shrub layer. In a layered planting this is woody mid-level structure between the understory and the ground. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Others in Rhododendron
- Cascade azalea Rhododendron albiflorum
- smooth azalea Rhododendron arborescens
- dwarf azalea Rhododendron atlanticum
- rhodora Rhododendron canadense
Similar role and hardiness
- fourwing saltbush Atriplex canescens
- big saltbush Atriplex lentiformis
- coyotebrush Baccharis pilularis
- Eastern Mojave buckwheat Eriogonum fasciculatum
- California buckthorn Frangula californica
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol RHMA3, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
- Quoted from USDA PLANTS: active growth period, Bloom, Bloom end, browse palatability, cold stratification, Drought tolerance, fall conspicuous, fertility requirement, fire tolerance, Flower color, flower conspicuous, foliage color, foliage porosity winter, foliage texture, frost free days min, fruit conspicuous, growth form, Growth rate, Hardiness zones, Lifecycle, lifespan, Light, Mature height, Minimum temperature, Native status, Nitrogen fixation, Nursery availability, precipitation max in, precipitation min in, propagation, resprout ability, root depth in, seed spread rate, Soil pH, Soil pH (upper), Tolerance of wet soil, Toxicity, vegetative spread rate, Water need.
- Derived by a fixed rule from those columns: Guild layer, Type.
Read our full data sources and methodology.
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