Culture
Best grown in medium to wet, well-drained soils in full sun. Does best in locations with abundant air and soil moisture. A good tree for northern and northwestern climates, but not for areas such as St. Louis where hot and humid summers with periods of drought are common.
Noteworthy Characteristics
Pseudotsuga menziesii, commonly called Douglas fir, is a very large conifer that grows 50-80' tall in cultivation, but to 300+' tall in the wild. Unique forked cone bracts distinguish this tree from all other conifers. The species is indigenous to coastal areas and up to 5500' in elevation in the mountains from British Columbia south to central California. Cones (to 4.5" long) are pendulous with protruding trident-shaped bracts. Flat, linear, spirally-arranged, dark green needles (to 1.5" long) with white banding beneath. Fallen or plucked needles leave raised circular leaf scars on the twigs. Needles are fragrant when bruised. Narrow pyramidal shape with branching to the ground when young. Trees become more cylindrical with age as they lose their lower branching, with older trees typically having branching only on the top 1/3 of the tree. This is an important timber tree in the Pacific Northwest. Pseduotsuga menziesii var. glauca is the Rocky Mountain variety of this tree. It grows at higher elevations (to 9500') with a slower growth rate, and has shorter cones (to 3"), blue-green needles and better winter hardiness. Var. glauca is the commonly cultivated variety of this tree for areas outside of the Pacific Northwest, and is clearly a better selection for midwestern climates than the species because of its better cold tolerance (species is hardy to USDA Zone 6, but var. glauca is hardy to Zone 4). Synonymous with and sometimes called Pseudotsuga taxifolia.
Genus name comes from the Greek words pseudo meaning "false" and Tsuga meaning "hemlock".
Specific epithet honors Scottish naval surgeon and botanist Archibald Menzies (1754-1842).
The common name honors David Douglas (1799-1834), Scottish botanist who introduced this species and a number of other North American conifers, flowering shrubs, and other plants into cultivation in Great Britain.
Problems
Fungal diseases such as shoestring root rot and laminated root rot can cause significant damage in monoculture plantings. Red ring rot and Douglas-fir beetle can also be problematic.
Uses
One of the largest tree species. A valuable timber tree and forest tree, but not really a great landscape tree for cities or towns. Growth of this magnificent tree should probably not be attempted in the St. Louis area.