FEBRUARY: BRISTLECONE PINE
Pinus aristata or Bristlcone Pine is a very hardy, drought tolerant, landscape specimen tree that works really well as a character pine or focal point for beautiful Boulder Colorado Landscapes. This is not the type of pine to use as a windbreak, or for privacy screening. It is very slow growing, having a bottlebrush appearance to the branches, with short needles arranged in clusters of 5 that can remain on the tree for up to 40 years. Some of the oldest trees on our planet are the Bristlecones found in the southwestern United States, many of which are now over 3,000 years old. There are really 3 species of Bristlecone pine…aristata, longaeva, and balfouriana. Here in Colorado, the species most available for residential landscapes is the aristata.
Most soils along the Front Range towns of Colorado are alkaline, and are perfectly suited to the bristlecone. Often, soil amendments are added to plants to bring the soil closer to neutral or acidic for evergreen species, but the Bristlecone prefers the alkaline soils. As with all new plantings, breaking up the clay with amendments is necessary, but do not overdo the compost amendments with the Bristlecone….it really prefers a rocky, dolomite or limestone type soil. Keep watered when newly planted just like with all new trees, but back off soon after establishment to prevent drowning and root rot. Good drainage is essential as it does not like to have wet feet. Once established, they will do just fine on the annual moisture we receive in Colorado. They can handle a bit more water, but are definitely on the low end of the water tolerance scale.
The Bristlecone species are invaluable to paleoclimatologists because they provide a history of moisture variations in the southwest United States through dendrochronology or tree ring dating which can go back almost 9,000 years using cross referencing. Even the locations of the oldest specimens are kept secret so they do not attract attention from people who might harm them.
For residential landscapes, the Bristlecone provides a unique specimen focal point from a design perspective. They are generally not available larger than 5-6 feet high due to their slow growing nature. The one in the picture is probably close to 30 years old and was planted as a small 4’ speicimen, and is now only about 9’ tall. Obviously the Bristlecone can handle full sun, but this speicimen was planted on the north side of a garage, does not get much direct sunlight except in the late afternoon in the summer, and seems to be doing just fine with that limited amount of light. Consider planting one as the center piece of a designed landscape. It will surely provide years of enjoyment.