western juniper
Juniperus occidentalis · Cupressaceae
western juniper (Juniperus occidentalis) is a perennial tree in the Cupressaceae family. It is native to North America. USDA records it as hardy in zone 3 and warmer, down to about -33°F.
⚠ Allelopathic. USDA flags this plant as releasing compounds that can suppress the growth of plants near it. Give neighbours extra room, and expect some companions to struggle regardless of how well their conditions match.
Both flags are quoted from USDA PLANTS, not inferred.
At a glance
| Type | tree USDA |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 33 ft USDA |
| Light | full-sun USDA |
| Water need | low USDA |
| Growth rate | slow USDA |
| Soil pH | 6–8.5 USDA |
| Bloom | May–June USDA |
| Flower color | Yellow USDA |
| Hardiness zones | 3 and warmer USDA |
| Guild layer | understory 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 needs full sun. USDA rates it as having low water needs once established. Its drought tolerance is rated high. It will not tolerate waterlogged soil — USDA rates its anaerobic tolerance as none. It is recorded on soils from pH 6 to 8.5 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 3.
Size and growth
At maturity it reaches about 33 ft, making it a substantial woody plant. It grows slowly.
Bloom period
USDA records a bloom period of May through June. Flowers are yellow.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is green, fine in texture. Its flowers are not conspicuous — a plant for form and foliage. 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 long.
What the site needs to provide
USDA records it across sites receiving 8 to 24 inches of annual precipitation. The low end of that band is genuinely arid, so it has a wide tolerance for dry country. It needs at least 150 frost-free days to finish its season. It roots to at least 12 inches. Fertility requirement: low — no feeding needed on ordinary garden soil.
Propagating it
It takes readily from seed, cuttings, bare root and container stock. Seed needs cold stratification — a period of moist chilling — before it will germinate, so sow in autumn or chill it artificially before a spring sowing. Its seed spreads at a slow 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 low. Its growth form is recorded as single stem.
Role in a guild
Understory. In a layered planting this is the layer beneath the canopy, tall enough to hold structure but shaded from above. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Others in Juniperus
- Chinese juniper Juniperus chinensis
- shore juniper Juniperus conferta
- common juniper Juniperus communis
- creeping juniper Juniperus horizontalis
Similar role and hardiness
- bigtooth maple Acer grandidentatum
- gray alder Alnus incana
- Canadian serviceberry Amelanchier canadensis
- gray birch Betula populifolia
- American hornbeam Carpinus caroliniana
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol JUOC, 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, Allelopathy, 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, Type, vegetative spread rate, Water need.
- Derived by a fixed rule from those columns: Guild layer.
Read our full data sources and methodology.
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