Western Hemlock

Western hemlock is the climax tree of Pacific Northwest rainforest, a graceful, shade-tolerant species you find reaching maturity beneath even taller Douglas-fir and western redcedar. The fine, pendulous branchlets and tiny, flattened needles give it a delicate, almost feathery appearance at distance. Young trees develop a distinctly conical outline, but mature specimens broaden into a pyramidal form, the leading shoot characteristically drooping. The needles, arranged in two ranks, are the smallest of our native conifers, and the cones are likewise tiny and round. In dense forest, hemlock grows taller and more slowly than in managed settings; in yards it can be a modest 30-40 feet.

Western hemlock is the most shade-tolerant conifer in Western Washington and the one to choose for deep forest conditions where Douglas-fir will thin and decline. It demands moist, acidic soils with good drainage and high organic matter; it is intolerant of drought and poor drainage alike. The tree's root system is shallow and fibrous, which allows it to forage rich surface soils but also makes it unstable in wind if planted in exposed sites. Watch for hemlock woolly adelgid, a non-native pest that has decimated hemlock populations in eastern North America, though it has not established in Washington. The species is very long-lived and, once established, becomes a reliable shade tree and forest understory anchor. Expect slow to moderate growth and remarkable longevity; this is a 400+ year old tree in the forest.