Chamaecyparis lawsoniana Cupressaceae
Port Orford Cedar, Lawson Falsecypress kam-e-SIP-a-ris la-so-ni-A-na
- Conifer (but not a true cedar), evergreen tree, 40-60 ft (12-18 m) tall, (180 ft in wild), narrow, pyramidal, buttressed trunk. Short ascending branches, drooping at the tips. Flattened frond-like twigs are arranged horizontally, developing white "X" markings on the underside. Leaves closely pressed in opposite pairs, mostly 2-3 mm, apex acute to acuminate, lateral pair keel-shaped and overlapping smaller facial pair, glands ("a dot") usually present. Male (staminate) pollen cones on the tips of branchlets, ovate to oblong, dark brown to red at pollen release. Female flowers inconspicuous, solitary, green to blue-green, developing into seed cones that are globose (round or spherical shape), 8 mm across, blue-green then ripening to brown in the first season, with about 8 scales.
- Sun or partial shade. Prefers well-drained, moist soil; shelter from winds.
- It is being attacked by a root rot fungus, Phytophthora lateralis, which is devastating the species in the US (typical result). Because of this, and susceptibility to other diseases, it is difficult
to grow in much of the US. Phytophthora lateralis is not wide spread in Europe and Phytophthora does not seem to be a major problem in England, since hundreds of cultivars are thriving
there (Am. Nur., Aug., 1995). However, an outbreak of P. lateralis has occured in northwestern
France. An online article published in Forest Pathology (15 NOV 2010) by C. Robin et al. documents the situation, it is
titled; Root and aerial infections of Chamaecyparis lawsoniana by Phytophthora lateralis: a
new threat for European countries. More recently, P. lateralis has been isolated from
diseased C. lawsoniana at several location in the United Kingdom (Green et al. Forest
Pathology, online 4 Jul. 2012).
- Nearly 300 types or cultivars have been selected from this species, many more than from any other conifer (Krüsmann,"Cultivated Conifers", p. 70). Some cultivators lose
their distinctive characteristics as they age, making them difficult to identify.
- Hardy to USDA Zone 5 Native range is along the coast in southwestern Oregon (the town of Port Orford is in the center of the range) and isolated inland areas at higher elevations, e.g., Siskiyou Mountains and on Mt. Shasta in northwestern California.
- lawsoniana: after Charles Lawson, a nurseryman in Edinburgh, Scotland, who grew trees from seed
sent to him in 1854 by William Murray while working on his "Notes on California Trees'. Lawson's
Falsecypress, as it is known in England and Europe, has been popular in their gardens since this first introduction.
See the following link from Kew Gardens about its discovery: http://apps.kew.org/trees/?page_id=140
- Oregon State Univ. campus: southeast of Ag. and Life Science building.