Will the Douglas Fir Grow in Zone 5?

Types

• Two natural forms of Douglas fir occur in the western United States. Douglas fir (Pseudotsuga menziesii var. menziesii) grows in the cooler, moister highlands nearest the Pacific Ocean in the Cascade Mountains westward. The interior Douglas fir, also called Rocky Mountain fir (Pseudotsuga menziesii var. glauca), occurs in the colder, slightly more arid highlands of the central and southern Rocky Mountains. The latter differs from the coastal Douglas fir in not growing as tall, slightly bluer green foliage and more seedlings grow and rejuvenate within a forest grove if containing interior Douglas firs.

Cold Hardiness

• Both coastal and interior Douglas fir trees will survive the winter cold temperature thresholds in USDA Zone 5. However, in parts of the country where winters are colder, and air markedly drier with lots of wind, the interior Douglas fir would be a better option. For example, in the treeless prairies of the Midwest, the cold and windy winters could be hard of a coastal Douglas fir, but not so for an interior Douglas fir. In the Northeast where native woodland diminish wind and winters are more humid because of proximity to the Atlantic Ocean, either variety could prosper.

General Indicators

• If your landscape already successfully supports growth of a healthy spruce tree, chances are a Douglas fir will also grow well, according to the University of Connecticut Plant Database. The Douglas fir grows best in a cool, moist but well-drained soil that is not alkaline in pH (7.2 or higher). Avoid planting it in an exposed site that is hot and dry in summertime. In fact, any climate within USDA Zone 5 that endures more than 90 days of summer temperatures above 86 degrees Fahrenheit is not an ideal climate for growing any Douglas fir tree.

Zone 5 Growing Areas

• Douglas fir trees both grow successfully at the Denver Botanic Gardens and at the Chicago Botanic Garden -- both located in USDA Zone 5. In the Great Plains, including the higher elevations of the Front Range, irrigation may be needed to ensure the Douglas fir is not stressed by overly dry conditions. Grow this fir in other zone 5 areas, such as in southern New England, the lower Missouri River Valley, as well as in a swath from Des Moines eastward to Albany.