white alder
Alnus rhombifolia · Betulaceae
white alder (Alnus rhombifolia) is a perennial tree in the Betulaceae family. It is native to North America. USDA records it as hardy in zone 4 and warmer, down to about -24°F.
At a glance
| Type | tree USDA |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 65 ft USDA |
| Light | shade USDA |
| Water need | high USDA |
| Growth rate | rapid USDA |
| Soil pH | 4.8–7.5 USDA |
| Bloom | September–November USDA |
| Flower color | Green USDA |
| Hardiness zones | 4 and warmer USDA |
| Guild layer | canopy 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 tolerates full shade. USDA rates it as having needs consistently moist ground. Its drought tolerance is rated low. It is recorded on soils from pH 4.8 to 7.5 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 4.
Size and growth
At maturity it reaches about 65 ft, making it a large tree that will dominate its site. It grows quickly.
Bloom period
USDA records a bloom period of September through November. Flowers are green.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is green, medium in texture. Its flowers are not conspicuous — a plant for form and foliage. Its active growth period is spring and summer. USDA rates its lifespan as long.
What the site needs to provide
USDA records it across sites receiving 20 to 125 inches of annual precipitation. It needs at least 200 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. 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 low, and it can resprout after damage. Its growth form is recorded as multiple stem.
Role in a guild
Canopy. In a layered planting this is the tallest layer of a planting — it sets the light budget everything beneath it lives on. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Others in Alnus
- European alder Alnus glutinosa
- gray alder Alnus incana
- speckled alder Alnus incana
- thinleaf alder Alnus incana
Similar role and hardiness
- Fraser fir Abies fraseri
- incense cedar Calocedrus decurrens
- pecan Carya illinoinensis
- shellbark hickory Carya laciniosa
- sugarberry Celtis laevigata
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol ALRH2, 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, 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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