Mountain Hemlock

Mountain hemlock is a subalpine conifer of high-elevation exposed ridges and snowfall-heavy zones, a small to moderate-sized tree with a distinctive, compact pyramidal form and graceful, drooping leader. The needles are flattened and aromatic, and the tiny cones are purple-red when young, becoming brown. The tree rarely exceeds 50-60 feet even in optimal alpine conditions and is often much shorter in harsh, windswept sites. In Western Washington lowlands, mountain hemlock is rare and typically performs poorly, but at higher elevations and in cooler microclimates, it can establish. The bark is thin, gray, and scaly. The tree's ability to grow in the harshest mountain environments (with deep winter snow and very short growing seasons) makes it a remarkable adaptation but also a difficult landscape subject at lower elevations.

In Western Washington lowlands, mountain hemlock faces significant limitations. The tree requires deep, consistent moisture, cool temperatures, excellent drainage, and full sun to part shade. It is susceptible to root and foliage diseases in maritime conditions and lacks vigor in lowland sites. Above 2,000 feet in the Cascade foothills, mountain hemlock grows in its native habitat and is appropriate for restoration plantings. For lowland sites, western hemlock, coastal Douglas-fir, and Alaska cedar are better adapted alternatives. This is a high-elevation specialist that performs best within its native range.