Limber pine

Sun

Full sun; tolerates light shade but develops a denser crown in open light.

Water

Moderate while establishing; drought-tolerant once established. Avoid constantly wet soil.

Soil

Well-drained sandy, gravelly or rocky soil, from slightly acidic to alkaline. Poor drainage is a greater problem than low fertility.

Height

30-50 ft (9-15 m), occasionally taller

Spread

15-30 ft (4.5-9 m)

Foliage

Evergreen. Dark green to blue-green needles in bundles of five, usually 2-3.5 in (5-9 cm) long. Young trees are broadly pyramidal; older trees develop more open, irregular crowns.

Growth

Slow, commonly 6-12 in (15-30 cm) a year under garden conditions.

Care needed

Low

• Drought tolerant
• Cold hardy
• Wildlife

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   7 ft (2 m)

2. After 1 year

   8 ft (2.3 m)

3. After 2 years

   9 ft (2.6 m)

4. After 3 years

   10 ft (2.9 m)

5. After 5 years

   12 ft (3.6 m)

About 32 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Mildly toxic: may upset a stomach

Native to

the US and Canada

Growth rate

Slow

• Plant with the root flare at soil level, allowing enough space for the full-sized tree rather than relying on pruning.
• Water deeply during dry spells for the first two or three growing seasons; let the surface soil dry between waterings.
• Spread 2-3 in (5-8 cm) of mulch over the root area, keeping it clear of the trunk.
• Avoid routine feeding; fertilize only if a soil test identifies a deficiency.
• Stake only if the root ball moves in wind, and remove supports after the first growing season.

Pruning. Prune only to remove dead, damaged or crossing branches, preferably in late winter during dry weather. Preserve the main leader and do not cut back into bare old wood, which rarely produces new shoots.

Late winter

Remove dead or damaged branches and check that ties or guards are not constricting the trunk.

Spring

Plant container-grown trees once the ground is workable, keeping the root flare exposed.

Late spring

Inspect new shoots and needles for aphids, scale insects and unusual browning.

Summer

Water young trees deeply during prolonged dry weather; avoid frequent shallow watering.

Autumn

Refresh mulch and water young trees before the ground freezes if autumn has been dry.

Winter

Keep de-icing salt away from the root area and avoid piling salt-contaminated snow around the tree.

• Use as a specimen in a sunny lawn or gravel garden, leaving room for its broad mature crown.
• Combine with junipers, boulders and drought-tolerant grasses for a mountain landscape.
• Plant in a loose group on a well-drained slope for year-round structure and shelter.
• Use its blue-green foliage as a quiet backdrop to flowering shrubs and perennials.

Garden styles it suits: Mountain lodge, Alpine rock garden, Desert / xeriscape, Wildlife garden, Winter interest and Low-maintenance.

Plant it with: Creeping juniper, Bearberry, Blue grama, Prairie dropseed, Sulphur buckwheat and Penstemon.

Wildlife: The large seeds feed nutcrackers, jays, squirrels and other wildlife. Birds use the evergreen branches for shelter and nesting, and seed-caching birds help disperse the tree.

• White pine blister rust can cause swollen, resinous branches and dieback. Have suspected infections assessed promptly; infected branches may be removable before the disease reaches the trunk, but trunk infections are often fatal.
• Bark beetles attack stressed trees, causing boring dust, resin patches and fading foliage. Reduce drought stress, avoid trunk injuries and seek local arboricultural advice quickly if an attack is suspected.
• Pine needle scale can produce white specks and thinning foliage. Confirm the pest, preserve beneficial insects and use a labelled treatment timed to the crawler stage if needed.
• Waterlogged roots cause yellowing, poor growth and root rot. Choose a freely drained site and correct excess irrigation rather than trying to compensate with fertilizer.

Not known to be toxic to people, cats or dogs, although swallowed needles can cause mouth or digestive irritation and resin can irritate skin. Safety for horses is not well established; keep needles and pruning waste out of feed and grazing areas.

• Whitebark pine (Pinus albicaulis)

  Both have five needles per bundle, but whitebark pine has short, thick-scaled cones that usually remain closed. Limber pine has longer cones that open at maturity to release their seeds.

• Eastern white pine (Pinus strobus)

  Eastern white pine generally has longer, softer, more drooping needles and long, slender cones with relatively thin scales. Limber pine has stouter needles and broader, heavier-scaled cones.

The name flexilis means flexible, referring to the pliable young branches that also give limber pine its common name.

Propagation. Usually grown from seed given a period of cold, moist stratification before sowing. Named cultivars are generally grafted by specialist nurseries; cuttings are difficult to root.

Accepted botanical name

Pinus flexilis

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Alberta, Arizona, British Columbia, California, Colorado, Idaho, Montana, Nebraska, Nevada, New Mexico, North Dakota and Oregon.

Measured

Soil pH 5.7 to 6.5. Average height 715 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.