About Cupressus arizonica var. arizonica
Hesperocyparis arizonica (synonym Cupressus arizonica var. arizonica) is a coniferous evergreen tree with a conic to ovoid-conic crown. It reaches heights of 10–25 m (33–82 ft), with a trunk diameter up to 55 cm (22 in). Its foliage grows in dense sprays, ranging in color from dull gray-green to bright glaucous blue-green. The leaves are scale-like, 2–5 mm long, and grow on rounded shoots that are not flattened. Its seed cones are globose to oblong, 15–33 mm long, with 6 or 8 scales, rarely 4 or 10. Seed cones start green, and mature to gray or gray-brown around 20–24 months after pollination. The cones stay closed for many years, only opening after the branch that bears them is killed, by a wildfire or other cause. This allows seeds to colonize the bare ground exposed by the fire. Male cones are 3–5 mm long, and release pollen between February and March. This tree is distributed mainly across northern Mexico, in the states of Chihuahua, Coahuila, Durango, Tamaulipas, and Zacatecas. It also grows in small areas of the southwestern United States, in the southern parts of Arizona, New Mexico, and Texas. In the United States, it grows at elevations of 1,000–1,500 m (3,000–5,000 ft), while in Mexico it can be found as high as 2,200 m (7,200 ft) in some forests. In the wild, this species usually occurs in small, scattered populations rather than large continuous forests. One known location where it grows is the Sierra Juárez and San Pedro Mártir pine–oak forests of Mexico, where it occurs alongside canyon live oak and California fan palm. Arizona cypress, as it is commonly called, is widely cultivated as an ornamental tree. Unlike Monterey cypress, it is highly resistant to cypress canker, a disease caused by the fungus Seiridium cardinale, and grows reliably in areas where this disease is common. The cultivar 'Pyramidalis' has earned the Royal Horticultural Society's Award of Garden Merit, confirmed in 2017.
