For information about how you could sponsor this page, see How You Can Help
Article from Bean's Trees and Shrubs Hardy in the British Isles
Article from New Trees by John Grimshaw & Ross Bayton
Recommended citation
'Hesperocyparis arizonica' from the website Trees and Shrubs Online (treesandshrubsonline.
The text below combines the accounts from New Trees (Grimshaw & Bayton 2009) and Trees and Shrubs Hardy in the British Isles (Bean 1976) which discussed this conifer under the old name Cupressus arizonica. We have moved these texts here, under the correct modern name with appropriate synonymy, to bring these accounts in line with modern taxonomic treatments. For an in-depth overview of the studies and ensuing taxonomic changes that prompted this change, see both the Hesperocyparis and Callitropsis genus accounts.
The main text for this and related taxa will be updated when sponsorship is forthcoming; if you would like to support the revision of these accounts please contact the editors.
TC, October 2024.
A tree to 75 ft in the wild state (sometimes taller in favoured localities); bark on young trees red, smooth, peeling in thin flakes, on mature trees dark brown, furrowed and fibrous. Leaves closely overlapping and scale-like, pale green to grey-green, more rarely blue-green, acutely pointed, about 1⁄16 in. long; resin-pits usually inconspicuous and inactive. Branchlets irregularly arranged, the final subdivisions four-sided, 1⁄20 in. in diameter. Cones short-stalked, globose, 3⁄4 to 1 in. in diameter, glaucous; scales six (rarely eight), slightly rising towards the middle, where there is a pyramidal, pointed boss.
Native of the S.W. United States and N. Mexico (where it may intergrade with the closely allied C. lusitanica); discovered by Greene in 1880 in S.E. Arizona and also found in S.W. New Mexico. Most of the trees cultivated in Europe as C. arizonica or “var. bonita” belong to the following species, which is a close ally and not recognised by all authorities:
specimens: Borde Hill, Sussex, by Kitchen Garden, 62 × 43⁄4 ft (1978); Exbury, Hants, 65 × 53⁄4 ft (1978); Westonbirt House, Glos., a fine tree, 72 × 51⁄2 ft (1982); Hergest Croft, Heref., in Park Wood, 66 × 51⁄2 ft (1978); Alton Towers, Staffs., 56 × 71⁄2 ft at 1 ft (1974); Stanage Park, Powys, 66 × 6 ft (1980); Mount Usher, C. Wicklow, Eire, 62 × 63⁄4 ft (1975); Avondale, Co. Wicklow, Eire, 82 × 73⁄4 ft (1980).
The clones ‘Conica’ and ‘Pyramidalis’, although similar, are not identical. The latter is somewhat broader than the former, and more silvery glaucous. Of neither has the history been ascertained. The cultivar-name ‘Pyramidalis’ apparently starts in the Hillier catalogue for 1928. The Dutch dendrologist den Ouden mentions ‘Conica’ in a work on conifers published in 1949, but the name was current in the trade (as C. arizonica conica). It was probably first distributed by a French or Italian nursery. To complicate matters, there is also ‘Glauca’, described in 1916 as being of conical habit, with juvenile, glaucous blue foliage.
In Britain, the commonest clone by far is ‘Pyramidalis’, of which the following examples have been recorded: University Botanic Garden, Cambridge, pl. 1937, 50 × 31⁄4 ft (1982); Silwood Park, Berks., 46 × 33⁄4 ft (1982); Brynderwyn, Powys, pl. 1936, 52 × 41⁄2 ft (1977); Cathays Park, Cardiff, 50 × 41⁄2 ft (1980).
Five varieties of Cupressus arizonica are recognised by Farjon (2001, 2005c), though prior to the revision by Little (1966) they were all regarded as separate species. The morphological characters that separate the varieties (bark colour and texture, leaf resin glands and leaf colour, cone serotiny) intergrade and may be the result of ecological factors. For these reasons, Watson & Eckenwalder (1993) employ a conservative taxonomic concept, recognising no varieties. Cupressus arizonica (including vars. arizonica, glabra and stephensonii) was described by Bean (B799, S199) and Krüssmann (K103). Although the species is a commonly grown garden plant, a key to the currently accepted varieties is provided below, adapted from Little (1966). All seem to be hardy and easy to grow wherever C. arizonica can be cultivated.
1a. | Bark of mature trees grey or dark brown, rough and furrowed | 2 |
1b. | Bark of mature trees reddish brown, smooth, peeling in thin, curling plates | 4 |
2a. | Cone scales open at maturity; Mexico (Baja California Norte) (see K105) | var. montana (Wiggins) Little |
2b. | Cones serotinous | 3 |
3a. | Leaf resin glands conspicuous and active; USA (California: Piute Mts.) (see K105) | var. nevadensis (Abrams) Little |
3b. | Leaf resin glands absent or inactive, rarely active; Mexico (Chihuahua, Coahuila, Durango, Tamaulipas, Zacatecas) (see B799, K103) | var. arizonica |
4a. | Leaf resin glands inactive or slightly active; seeds usually over 5 mm long, not glaucous; Mexico (Baja California Norte), USA (California: Cuyamaca Mts.) (see B800, K105) | var. stephensonii (C.B. Wolf) Little |
4b. | Leaf resin glands very active, resulting in white flecks of resin on the foliage; seeds usually 4–5 mm long, glaucous; USA (Arizona: Coconino, Gila, Maricopa, Yavapai Counties) (see B799, S199, K103) | var. glabra (Sudw.) Little |