Abies concolor – Colorado White Fir (western North America)
Habit: An impressive, conical large tree, 20-25 (30) m tall, 4-6 (8) m wide; initially very symmetrically conical, later more loose with a rounded crown; branches symmetrically arranged in layers; initially medium-growing, 60 cm a year, then slow-growing, 30 cm a year.
Leaves: 5-8 cm long, intense bluish to grey-green needles, slightly crescent-shaped, arching upward, pectinate; shoots silvery grey, light yellowish grey in winter.
Roots: Adaptable, shallow to deep roots; can be easily transplanted; sensitive to heavy soil, very sensitive to soil compaction.
Demands: Sun to light shade, tolerates heat, but prefers cool areas, frost hardy; good for urban environments, sufficiently resistant to pollution, wind-resistant.
Soil: Moderately dry to fresh, tolerates the longest droughts of all firs once established; acidic to slightly alkaline; prefers well-drained, sandy or gravelly-loamy soil, avoids heavy loam or clay.
Native habitat: In the high, mountainous region of the Rocky Mountains, Abies concolor often joins varieties of Ceanothus, Pinus, Quercus, Ribes and Symphoricarpos.
Hardiness: Zone 5