Family: Cupressaceae
Common Name: False Cypress

This genus from North America and eastern Asia includes only seven wild species of these tall forest trees, although it has produced a greater number of ornamental cultivars than any other conifer group. The false cypresses arc very useful garden subjects owing to the great diversity of form and colour their many cultivars provide, and include many of the dwarf conifers favored for rock gardens and tubs, or as bonsai specimens. The tall-growing wild forms are not grown as often as the cultivars, with the exception perhaps of C. lawsoniana. However, if provided with sufficient space and appropriate conditions, they will all make very handsome trees.

Species

C. lawsoniana, Lawson cypress, is found growing naturally in the humid, coastal forests of north-western North America. This majestic forest tree has been known to attain heights of 60 m (200 ft) in the wild and can reach 30 m (100 ft) in cultivation, given the appropriate soil and climatic conditions. It matures to a narrow, pyramidal form, with a dense curtain of gray-green foliage. A myriad of cultivars is now available in a multitude of forms, among them dwarf, juvenile-foliaged, golden, variegated and blue-gray. Cultivar 'Allumii' develops a narrow, pyramidal shape, with deep blue-gray foliage in erect, crowded, flattened sprays. It grows 2-5 m (6-16 ft) tall. 'Ellwoodii' is a dense, compact, columnar or oval form to about 3 m (10 ft), with deep blue-green juvenile foliage. 'Erecta' is normally 2-3 m (6-10 ft) tall but can reach 6 m (20 ft) or more with age. It has a pyramidal shape, with very thick, green foliage. 'Erecta Aurea' is similar to 'Erecta' but smaller and slower growing, with golden yellow foliage on the outside and green in the center. 'Retched' grows to a pyramidal shape, 2-5 m (6-10 ft) tall, with blueish green, semi-juvenile foliage. 'Minima' is a dwarf, globular form, growing to a height of 30-S0 cm (12-20 in) with densely packed, fan-like, plain green branchlet sprays. 'Minima Aurea' and 'Minima Glauca' have respectively golden yellow and blue-green foliage. 'Nana' is similar to 'Minima' but with a more central stem and a more upright habit; it also has a slightly pointed top. 'Silver Queen' is a broadly pyramidal type, with an extended apex, which reaches a height of 3-6 m (10-20 ft). The foliage is borne in large, flat sprays and the very pale green, almost white, younger branchlets change to a deeper green in the center of the plant. 'Wisselii' attains a pyramidal, open shape, has a height of 2-5 m (6-16 ft) and has many outward-pointing or erect narrow spires of blue-gray foliage.

C. obtusa, hinoki cypress, grows to a fine, tall tree, valued for its timber in its native japan and Taiwan. It has flattened branchlet-sprays. The leaves on the undersides of the sprays are distinctively edged in bright, blueish white. This species is almost unknown in cultivation, but many cultivars are available, of which the following is a selection. 'Crippsii' is very popular and grows well in exposed coastal areas and in poor, sandy soils. Broadly based, it grows in a pyramidal shape to 6-8 m (20-26 ft) with age. It is covered in crowded, out-curving, bright golden yellow foliage which contrasts with the green of the interior. 'Fernspray Gold' is slow growing to 1-2 m (3-6 ft) tall. It has long, plume-like branches nodding at the tips and fresh green, fern-like foliage. The short, lateral branchlets are not flattened as in most of the species and cultivars.

C. pisifera, sawara cypress, from Japan, also grows to a very tall tree in its native habitat. It is identifiable by the long, sharp points of its adult leaves, which give the foliage a prickly feel. The many cultivars make excellent garden plants as they are more tolerant of strong sun and dry soil conditions. 'Boulevard', a semi-dwarf, columnar form, to 2 m (6 ft), is one of the most appealing blue-foliaged cultivars in the genus. It has juvenile foliage, with short, crowded branchlets and needle-like leaves, dull blue-green above and brilliant, blueish white beneath. 'Filifera Aurea' has a spreading habit, with pendulous side-branches which droop down below the stem base. It grows 1.5-3 m (5-10 ft) tall and is very suitable for rockeries and tubs. The foliage is tipped with gold in spring and summer and pale lemon yellow in autumn and winter. 'Plumosa Compressa' rarely grows to more than 20 cm (8 in) tall. It has a dense globe of prickly, juvenile, yellowish green foliage and densely packed branchlets. 'Squarrosa' has been known in Japan since the end of the 18th century. Broadly columnar to conical in habit, it reaches 8-10 m (26-33 ft) in height as it ages. The juvenile, pale blue-gray foliage in quite loose, feathery sprays develops pinkish tones in winter.

C. thyoides, swamp white cedar, zone 5, is a native of North America where it usually occurs as a rather scrubby tree in poor, swampy ground. Under cultivation, however, this species can grow to a columnar tree of 7-15 m (23-50 ft). The fine branchlets are grouped into many tiny, flattened sprays which appear at different angles, giving an irregular appearance to the dull green foliage. Cultivars include 'Andelyensis', a columnar, compact form, which grows to 3 m (10 ft), with blue-gray foliage; and 'Ericoides' growing to 1-2 m (3-6 ft), with a habit which can be upright oval to pyramidal. The juvenile bronze-green foliage turns to a dull bronze-purple colour in the winter.

Cultivation

The species are fairly easy to grow, needing only light and well-drained, reasonably deep soil. Most of the coloured foliage cultivars need a lot of sun so that the colour can develop to its true intensity. Nearly all can be shaped as required by judicious pruning or pinching out of the shoots, but they will not normally regenerate from the cut stumps if the larger branches are pruned off. It intensive pruning is necessary, make sure that the stumps are covered by the surrounding foliage. It is possible to propagate both the species and the cultivars from cuttings, although some are difficult to strike. Root semi-ripe cuttings in late summer in a garden frame. They should have a portion of brown or ripe wood at the base to ensure rooting. Species can be raised from seed sown in spring in an outdoor seed bed. Some dwarf cultivars are propagated commercially by grafting in late winter but this is not an easy technique for the home gardener.

Climate

Zone 6 for the majority of the species.