March, 2020: Douglas Fir
Boulder Colorado area landscapes – plant of the month
Douglas Fir or Pseudotsuga menziesii is a very large conifer tree that grows native in three areas of the Americas: The coast ranges of California, north through Oregon and Washington and into British Columbia (variant menziessi); the Rocky Mountains (variant glauca); and the Mexican variety (variant lindleyana), growing south from the southern part of California to Oaxaca. The largest, the coast variety can reach 330’ in height. The Rocky Mountain ‘glauca’ variant will grow to 150’ but in landscapes will not top 80’ x 20’ wide. It has ornamental landscape uses in our Boulder, Colorado landscapes where there is space for it to thrive. They can be found a few miles to the west of Boulder on north facing slopes of Boulder Canyon.
Douglas Fir like acidic to neutral soils, so a good acidic soil amendment when planting is helpful due to our naturally alkaline soils on the plains of the Front Range. They like moderate water, as indicated by their preference to north slopes on lower elevations of Boulder Canyon, but can tolerate drought once fully established. They are attractive in the landscape because, like other fir, their needles are soft to the touch, unlike Spruce which can be rather prickly. If you are planting a group of mixed species coniferous evergreens, consider adding in a few Douglas Fir to add character and diversity to your windbreak or privacy screenings.
Photos by Dave Powell Amazon.com and Connon Nursery.