Scarification: Soak in water, let stand in water for 24 hours
Stratification: cold stratify for 30 days
Germination: sow seed 1/4" deep, tamp the soil, mulch the seed bed
Other: fall sowing in mulched beds is prefered to artificial stratification
Introducing the Pseudotsuga menziesii var. glauca Douglas Fir - a versatile and highly sought-after evergreen conifer native to western North America. This tree, also known as the Rocky Mountain variety, is a popular choice for landscape and timber companies alike.
The common name, Douglas Fir, originates from the Scottish botanist, David Douglas, who first discovered and reported on the unique characteristics of this species. However, it is important to note that Pseudotsuga menziesii var. glauca is not a true fir but belongs to the genus Pseudotsuga.
This variety of Douglas Fir thrives at higher elevations, growing up to 9,500 feet, and exhibits a slower growth rate compared to its counterparts. With its shorter cones, blue-green needles, and excellent winter hardiness, var. glauca is the commonly cultivated variety for areas outside of the Pacific Northwest. This makes it an ideal choice for midwestern climates, as it shows better cold tolerance, thriving in USDA Zone 4.
The Douglas Fir's versatility is showcased in its numerous applications. It can be planted as a specimen tree to add beauty and grandeur to any landscape or used for mass screening purposes. Additionally, it is a preferred choice for Christmas trees, known for its attractive appearance and longevity.
One of the standout features of the Douglas Fir is its useful wood and quick growth, which has made it a favored crop for timber companies. After clear-cutting an area, these companies often replant with Douglas Fir, taking advantage of its abundant seeds. These seeds also serve as a crucial food source for small mammals such as mice, voles, shrews, and chipmunks in western Oregon.
The Coast Douglas Fir variety (var. menziesii) is primarily found along coastal regions from British Columbia to central California. On the other hand, the Rocky Mountain or Interior Douglas Fir variety (var. glauca) replaces it further inland. It intergrades with the Coast Douglas Fir in the Cascades of Washington and British Columbia, extending northward to central British Columbia and southeastward to the Mexican border. The Mexican Douglas Fir is often considered a part of the P. menziesii species and is found as far south as Oaxaca.
When grown in the proper environment, the Douglas Fir does not face any significant insect or disease problems. It thrives best in medium to wet, well-drained soils under full sun exposure. Abundant air and soil moisture are essential for optimal growth.
While the Douglas Fir is a remarkable tree in terms of size and timber production, its suitability as a landscape tree for urban areas is debatable. Due to its preference for northern and northwestern climates, it may not fare well in regions with hot and humid summers accompanied by periods of drought, such as St. Louis.
In conclusion, the Pseudotsuga menziesii var. glauca Douglas Fir is a unique and highly valued conifer species, recognized for its beautiful appearance, quick growth, and versatile applications. Whether as a specimen tree, Christmas tree, or timber crop, it continues to be a favorite among both nature enthusiasts and industry professionals.