1280 Pinus flexilisCommon Names: limber pine,Rocky Mountain white pine Family: Pinaceae (pine Family)
Limber pine is often a low growing, many branched, scruffy looking tree. On good sites it becomes a broadly cone shaped tree that gets flat topped with age. It has a short, often crooked trunk and stout, drooping branches that turn up on their tips. Limber pine can get 50-70 ft (15-21 m) tall, with a canopy spread of 20 ft (6 m) or so, but on rocky ledges and bluffs it often hangs on as a large, spreading shrub. Near the timber line, limber pine grows as a sprawling ground cover. Limber pine has smooth gray bark that becomes furrowed with age. Branchlets and young shoots are yellowish and surprisingly flexible. Needles are dark green, sometimes slightly bluish, 2-3 in (5-8 cm) long, and borne in fascicles of five. They are crowded on the branch tips and persist for five or more years before being replaced. Female cones are yellowish brown and 3-6 in (8-15 cm) long; male cones are reddish.
‘Vandewolf’s Pyramid’ is faster growing and has foliage more bluish than the species. ‘Glauca Pendula’ is a wide spreading, ground hugging shrub that is sometimes grafted onto a standard to create a weeping tree. ‘Glenmore’ has silvery blue foliage. ‘Millcreek’ has very bluish needles. ‘Nana’ is a slow growing bushy dwarf with short needles.
Pinus flexilis occurs in scattered populations in the Rocky Mountains, from New Mexico, Arizona and California, north to Alberta. Limber pine grows singly or in small groves at elevations between 5000 ft (1500 m) and 12000 ft (3600 m), often on rocky ridges, peaks and exposed bluffs. It is nowhere abundant. Limber pine is often associated with Douglas-fir (Pseudotsuga menziesii), ponderosa pine (Pinus ponderosa) and Engelmann spruce (Picea engelmannii) at lower elevations, and with mountain hemlock (Tsuga mertensiana), bristlecone pine (Pinus longaeva) and lodgepole pine (Pinus contorta) at higher elevations.
Light: Limber pine does best in full sun, but tolerates partial shade. Moisture: : Limber pine tolerates dry soils better than most pines, but does best on moist, well drained soils. Hardiness: USDA Zones 4 - 7 . Propagation: The cones of limber pine drop to the ground and shed their seeds in their second year. Seeds are best stratified under near-freezing temperatures for a couple months before sowing.
Limber pine is a long lived and slow growing tree that tolerates high wind and dry, rocky soils better than other pines. This is a trouble free evergreen that requires little maintenance and does very well in cultivation outside its native range. Limber pine has a fine, dense texture and has been used as a screen and a windbreak. With its horizontal to slightly pendulous branches that turn up gracefully on the ends, limber pine makes a very handsome specimen tree.
The wood is soft, light weight and usually full of knots. It is used for boxes, railroad ties, mine timbers, posts and locally for fuel. Limber pine is harvested along with (and not distinguished from) the more abundant ponderosa pine. The seeds are eaten by numerous kinds of birds and rodents.
The smaller branches are so limber they can be tied in knots. Some individuals of limber pine are more than a thousand years old.
Steve Christman 2/6/17