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polar willow

Salix polaris · Salicaceae

polar willow (Salix polaris)
Photo: no rights reserved · CC0 · via iNaturalist

polar willow (Salix polaris) is a perennial shrub in the Salicaceae family. It is native to North America. USDA records it as hardy in zone 1 and warmer, down to about -62°F.

At a glance

Typeshrub USDA
Lifecycleperennial USDA
Native statusnative USDA
Mature height0.2 ft USDA
Growth ratemoderate USDA
Soil pH5.5–8.5 USDA
BloomMarch–May USDA
Flower colorPurple USDA
Hardiness zones1 and warmer USDA
Guild layerground-cover Derived

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

Its drought tolerance is rated none — it needs reliable moisture. It handles periodically wet ground (USDA rates its anaerobic tolerance medium). It is recorded on soils from pH 5.5 to 8.5 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 1.

Size and growth

At maturity it reaches about 0.2 ft, making it a low, mat-forming plant. 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 green, coarse in texture. Its flowers are not conspicuous — a plant for form and foliage. USDA rates its lifespan as short, so plan on replacing or resowing it rather than treating it as permanent structure.

What the site needs to provide

USDA records it across sites receiving 4 to 39 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 47 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

Propagate it from seed, cuttings and sprigs. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a rapid rate. It spreads vegetatively at a moderate rate.

Resilience and wildlife

Its fire tolerance is rated medium, and it can resprout after damage. Its growth form is recorded as rhizomatous.

Role in a guild

Ground cover. In a layered planting this is the lowest layer — it shades soil, holds moisture, and suppresses weeds. The layer is derived by a fixed rule from growth habit and mature height.

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Tags

deciduouswet-tolerantsandy-soilspreadingnativeground-cover

Related plants

Others in Salix

Similar role and hardiness

Where this data comes from

Every value on this page comes from the USDA PLANTS database record for symbol SAPO, 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.

Read our full data sources and methodology.

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