Corkbark Fir

Corkbark fir (*Abies lasiocarpa* var. *arizonica*) is a slow-growing evergreen conifer native to high mountains of Arizona, New Mexico, and southern Colorado. Its glaucous blue-green needles and unusually thick, pale corky bark distinguish it from typical subalpine fir, while its narrow, spire-like form makes a distinctive specimen or screening tree for cool-climate landscapes. ## Landscape role Give this fir space as a long-lived focal point or a narrow evergreen screen. Although it is smaller than many true firs, mature corkbark firs can reach roughly 15–17 m (50–56 ft); the tree is not a compact shrub, and young plants take time to develop. Its slender crown and pale bark provide year-round structure, especially in naturalistic conifer plantings. North Carolina State Extension lists screening as a landscape use for the species. ## Growing conditions Choose a cool-summer site in full sun or partial shade. Subalpine firs are adapted to cool, humid mountain climates and can struggle with sustained heat and drought. Provide acidic, moisture-retentive but well-drained soil; the USDA Forest Service describes naturally occurring fir soils as generally acidic and notes good growth in well-drained, fine- to medium-textured soils. Water during establishment and dry spells rather than treating this as a water-saving tree. Hardiness references differ: Trees and Shrubs Online gives Zones 5–6 for var. *arizonica*, while the broader NC State species profile lists Zones 4a–7a. ## Identity and sourcing The catalog name “Arizonica” refers to a naturally occurring botanical variety, commonly written *Abies lasiocarpa* var. *arizonica* in botanical references. It is not a branded cultivar, so a cultivar breeder, commercial brand, and plant patent do not apply. Trees and Shrubs Online traces its introduction into cultivation to Dr. Purpus and the Darmstadt Botanic Gardens around 1900; that is a horticultural introduction, not a named breeder attribution. ## Sources - Trees and Shrubs Online: Corkbark Fir — variety identity, bark, foliage, mature specimens, and horticultural history. - USDA Forest Service: Silvics of North America — recognized varieties, native range, climate, soils, and growth. - North Carolina State Extension: Subalpine Fir — landscape use, light, soil, growth rate, and maintenance. - Oregon State University Landscape Plants — species form, foliage, and the smaller cork-fir variety. ## Maintenance The species is rated low maintenance, but it still needs a suitable climate and dependable moisture while young. Keep the root zone evenly moist during establishment and extended dry periods, and avoid poorly drained, saturated ground. Routine shaping is unnecessary for a naturally narrow crown; remove dead or damaged branches as needed.