Culture
Grow in average, medium moisture, well-drained soils in full sun. Best grown in moist, well-drained soils, however species plants are rather adaptable, often being found growing in high alpine areas in the wild in dry, rocky soils. It forms a large taproot and is difficult to transplant once established in the landscape. Although adaptable, limber pine does not generally perform well in the St. Louis climate, and is not recommended for planting south of USDA Zone 7.
Noteworthy Characteristics
Pinus flexilis, commonly called limber pine, is primarily found in the Rocky Mountains from Canada to New Mexico at elevations of 5,000 to 12,000 feet. It typically grows 25-60’ tall with a pyramidal habit maturing over time to a more rounded form. However, in exposed high alpine sites at or near tree line, it may also be seen growing in very dwarf shrubby shapes twisted and contorted by the extreme elements. It features dark green to bluish green needles (to 3.5” long) in bundles of five and short-stalked, thick-scaled, brown cones to 8” long. Cones fall to the ground without disintegrating.
Genus name comes from the Latin name for pines.
The specific epithet is in reference to the flexible (limber) branchlets/twigs.
‘Cesarini Blue’ is an upright, compact cultivar that features the bluest needles found on any of the P. flexilis selections. Needles are commonly described as being powdery blue. This is a narrow pyramidal tree that typically grows very slowly to only 6-7' tall and to 3' wide over the first 10 years, eventually rising over time to as much as 20-25' tall.
Problems
Limber pine is generally considered to be an adaptable, low-maintenance tree with few problems. It is susceptible to certain rots and blights, but its most dangerous enemy is white pine blister rust which is a bark disease that is usually fatal. Species of (e.g., currants and gooseberries) are the alternate host for white pine blister rust and should not be planted in areas where limber pines or white pines are under attack. White pine blister rust is not considered to be a problem in Missouri, however. Aphids, weevils, spider mites and scale may appear.
Uses
Good compact choice for small yards.