Horticulture/Chamaecyparis

Chamaecyparis is genus of conifers in the family Cupressaceae, native to eastern Asia and western and eastern North America. It is one of several genera within the Cupressaceae that have the common name cypress. Synonyms include Retinispora Siebold & Zucc. and Retinospora Carr.

There are a great number of cultivars available among the species with a wide range of shapes, sizes, and leaf colors.

Description
They are medium-sized to large evergreen trees growing to 20–70 m tall, with foliage in flat sprays. The leaves are of two types, needle-like juvenile leaves on young seedlings up to a year old, and scale-like adult leaves. The cones are globose to oval, with 8-14 scales arranged in opposite decussate pairs; each scale bears 2-4 small seeds.

Growing conditions
Four species (C. lawsoniana, C. obtusa, C. pisifera, and C. thyoides) are of considerable importance as ornamental trees in horticulture; several hundred cultivars have been selected for various traits, including dwarf size, yellow, blue, silvery or variegated foliage, permanent retention of juvenile leaves, and thread-like shoots with reduced branching. In some areas, cultivation is limited by ../Phytophthora/ root rot diseases, with C. lawsoniana being particularly susceptible to ../Phytophthora lateralis/.

Species
There are five or six species, depending on taxonomic opinion:
 * ../Chamaecyparis formosensis/. Taiwan.
 * ../Chamaecyparis lawsoniana/. Western North America.
 * ../Chamaecyparis obtusa/. Japan.
 * ../Chamaecyparis pisifera/. Japan.
 * ../Chamaecyparis taiwanensis/. Taiwan.
 * ../Chamaecyparis thyoides/. Eastern North America.

C. taiwanensis is treated by many authors as a variety of C. obtusa (as C. obtusa var. formosana).

Another species which used to be included in this genus, as Chamaecyparis nootkatensis, has now been transferred on the basis of strong genetic and morphological evidence to the separate genus ../Callitropsis/ as ../Callitropsis nootkatensis/, or back to Cupressus nootkatensis (the name it was originally described under in 1824).

Uses
The wood is scented, and is highly valued, particularly in Japan, where it is used for temple construction.

Maintenance
Pruning can be done in winter. Most species tolerate shearing and can be grown as hedges or topiaries.

Propagation
Cuttings, grafting, or seed.

Pests and diseases
../Blight/: ../Root Rot/ ../Rusts/ ../Scales/ ../Weevils/ ../Caterpillars/ ../Mites/ Chamaecyparis species are used as food plants by the larva of some Lepidoptera species including Juniper Pug and Pine Beauty.
 * ../Phomopsis juniperovora/
 * Seiridium or Coryneum Blight and Canker: ../Seiridium cardinale/
 * ../Phytophthora lateralis/ Problem in Pacific Northwest.
 * ../Phytophthora cinnamomi/
 * Witches Broom (Rust): ../Gymnosporangium ellisii/, Alternate hosts in ../Myrica/ and ../Comptonia/
 * Spindle Burl Gall (Rust): ../Gymnosporangium biseptatum/, Alternate host in ../Amalanchier/
 * Juniper Scale: ../Carulaspis juniperi/
 * Arborvitae Weevil: ../Phyllobius intruscus/
 * Imperial Moth: ../Eacles imperiales/
 * Bagworm: ../Thyridopterix ephemeraeformis/
 * Spruce Spider Mite: ../Oligonychus ununguis/