Chamaecyparis lawsoniana

9 Jan

Chamaecyparis lawsoniana (30/12/14, Kew Gardens, London)

Position: Full sun to partial shade

Flowering period: Spring

Soil: Well drained, moist

Eventual Height: 40m

Eventual Spread: 8m

Hardiness: 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b

Family: Cupressaceae

Chamaecyparis lawsoniana Leaf (30/12/14, Kew Gardens, London)

Chamaecyparis lawsoniana is a fast growing, densely columnar, large, uniform evergreen tree. The mid-green leaves are arranged in feathery flat sprays, are scale like, are 2mm wide, these produce a sour parsley scent when crushed. The trunk may achieve a diameter of 2m. The bark is reddish/ purplish and spongy and fibrous in vertical strips. This tree is monoecious and flowers in spring, the male flowers are white and turn red. The female cones are initially green, maturing to brown, are up to 1cm across and ripen in the first year after pollination.

Chamaecyparis lawsoniana, commonly known as the Lawson Cypress or Port Oxford Cedar (although it is not a Cedar), is native to western United States. It was introduced into the UK by collectors working for the Lawson and Son nursery of Edinburgh in 1854. In the USA this tree is threatened by the fungal pathogen Phytophtora lateralis both in the wild and in horticultural planting. As the spores of Phytophtora lateralis are spread through water, trees located near water are more susceptible to this pathogen. It is considered to be ‘vulnerable’ according to ‘The IUCN Red List of Threatened Species’. This species is the parent of approximately 200 cultivars.

Chamaecyparis lawsoniana Seed (30/12/14, Kew Gardens, London)

The etymological root of the binomial name Chamaecyparis is derived from the Greek chamea ‘dwarf’ and kupeiros the ancient Greek name for the Cypress (ironically this is not a dwarf tree). Lawsoniana is named after the Scottish nursery that discovered tree and brought it to the UK.

The landscape architect may find Chamaecyparis lawsoniana useful as a large specimen evergreen tree, particularly in shady locations. It may also be planted and maintained as an effective evergreen hedge.

Ecologically Chamaecyparis lawsoniana is of little value to wildlife.

Chamaecyparis lawsoniana Bark (30/12/14, Kew Gardens, London)

The Royal Horticultural Society has given many of the Chamaecyparis lawsoniana cultivars their prestigious Award of Garden Merit but not the species.

Chamaecyparis lawsoniana prefers moist, well-drained soils. It will tolerate most pH of soil.

Chamaecyparis lawsoniana requires little maintenance. If maintaining as a hedge it should be cut outside of the bird nesting season. It will not tolerate hard pruning.