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Larix occidentalis

western larch

Pinaceae

Inland Pacific Northwest of North America

Drought Tolerant

Native to North America

SunFull Sun

WaterMedium · drought-tolerant

HardinessZones 4–7

Overview

Larix occidentalis is a tall deciduous conifer reaching 100-180 feet (30-55 m) tall and 24-36 inches (60-90 cm) trunk diameter at maturity, with mature specimens occasionally exceeding 200 feet (60 m). The crown is narrow and conical when young, becoming open and irregular with age; lower branches are typically self-pruning to leave a clean bole on mature trees. Bark is reddish-brown, thick (up to 6 inches / 15 cm at the base), and deeply furrowed into rectangular plates on old trees. Needles are soft, pale to bright green, 0.8-1.6 inches (2-4 cm) long, borne in clustered tufts of 14-30 on short spur shoots and singly on new long shoots. Needles turn bright yellow in October before dropping, leaving bare branches through winter. Cones are oblong, 1-1.5 inches (2.5-4 cm) long, with bracts protruding beyond the scales; mature cones turn purplish-brown and persist on branches for 1-2 years. Pollen cones release pollen in May. Trees take 20-30 years to begin producing cones and live 400-700 years on suitable sites. Wood is dense, durable, and historically used for poles, ties, and shipbuilding.

Native Range

Native to the inland Pacific Northwest of North America, occurring from southeastern British Columbia south through northeastern Washington, northern Idaho, and western Montana, with isolated populations in northeastern Oregon. Found in moist montane forests, particularly on north-facing slopes and along streams, at 2,000-7,000 feet (600-2,150 m) elevation; occurs typically on deep, moist, well-drained soils.

Suggested Uses

Used as a specimen tree in large landscapes, parks, and naturalistic plantings at minimum 30-40 ft (9-12 m) spacing from buildings and other large trees. Suited to montane and cool-summer climate gardens, restoration plantings within the native range, and large estate landscapes. Performs poorly in urban heat islands, small residential lots, hot-summer climates, and zones outside USDA 4-7.

How to Identify

Distinguished from L. lyallii (subalpine larch) by lower elevation distribution (2,000-7,000 feet vs. 5,500-9,000 feet), longer needles (0.8-1.6 inch / 2-4 cm vs. 0.6-1.4 inch / 1.5-3.5 cm), and hairless twigs (vs. white-woolly in L. lyallii). Differs from L. laricina (eastern tamarack) by larger size (typically 100-180 ft / 30-55 m vs. 50-75 ft / 15-23 m) and western inland distribution. Cones have protruding bracts that exceed the scales; needles turn bright yellow before dropping in October.

Appearance

Size & Dimensions

Height100' - 180'

Width/Spread30' - 50'

Reaches mature size in approximately 80 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~2 weeks

Spring

Pollen cones release pollen from late April through early May, before or as new needles emerge. Female (seed) cones develop through summer, ripening in September and shedding seed in October-November. Cones persist on branches for 1-2 years after seed release. Wind disperses pollen and seed; no insect or animal pollination is involved.

Detailed Descriptions

Flower Description

pollen cones yellow; seed cones reddish then purplish-brown

Foliage Description

pale to bright green; turning bright yellow in fall

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 7.0(Neutral)

357912

Soil Types

loam rocky

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

60-100 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Water young trees deeply every 7-10 days during the first three growing seasons; established trees in their native range need no supplemental irrigation but may benefit from deep watering during multi-year drought. Plants in lowland or warm-climate sites suffer from heat stress, premature needle drop, and reduced vigor. Larch casebearer (Coleophora laricella) defoliates trees periodically in cultivated populations; biological control by parasitic wasps now reduces damage. Western larch dwarf mistletoe causes witches' brooms but rarely kills mature trees. Fall needle drop produces 2-4 inches (5-10 cm) of leaf litter annually under mature trees. Trees in cultivation reach mature dimensions in 60-100 years.

Pruning

Prune dead or damaged branches in late winter or early spring before bud break. Established trees rarely need structural pruning; the natural form develops without intervention. Remove lower branches if a clear bole is desired, up to a maximum of one-third of total tree height. Topping severely damages the natural form and produces weak watersprout regrowth.

Pruning Schedule

winterearly spring