By Jim McCausland, Sunset senior garden writer
Doubtless one of the most graceful conifers anywhere, Port Orford cedar (Chamaecyparis lawsoniana) now has the advantage of disease resistance. That’s no small thing. A wicked fungus called Phytophthora lateralis has decimated all previous forms of this lovely tree both in gardens and in its small native range along the California-Oregon border.
In the landscape, full size Port Orford cedar grows about 70 feet tall and narrow (pictured at right), but its lacy, drooping branch tips and its graceful pyramidal form save it from the indignity of looking like either a pillar or an exclamation point. Several excellent, smaller-scale selections have been made and sold, and all have been subject to P. lateralis. But researchers at Oregon State University have found disease-resistant Port Orford cedars, and Monrovia Nursery has chosen the 'Guardian' series from these to use as understock for existing varieties. The idea here is that since the fungus can't get past the disease-resistant understock, it will never affect the susceptible variety that's grafted on top of it.
The first to be released in small quantities (just 400 this year) is ‘Silberstar’, the silver-blue form pictured at left that will grow about 35 ft. tall and half as wide. Next year, more than 3,000 disease-resistant Port Orford cedars will be released, including 'Golden King', which is the same size as 'Silberstar', but with blue-green foliage tipped in gold; a six-foot dwarf called ‘Blue Surprise’; and a ten-foot golden variant called ‘Yvonne’.
Even apart from Port Orford cedar's usefulness in the garden, it makes a fascinating study. Its thick bark helps the tree survive wild fires, its oil has been used an an insecticide, and its beautiful wood neither shrinks nor swells much when it goes through wet-dry cycles. That has made it a top pick for outdoor timber-frame construction—the example below was built by Jim DeSantis of Silver Creek Timber Works, Silverton, Oregon, (503) 932-1395—and for boat-building. Sir Thomas Lipton (think Lipton tea), had all his racing yachts built from Port Orford cedar. It has also been extensively used for making coffins and temples by Asian woodworkers, especially after their own Hinoki cypress (a closely related Japanese tree with some of the same traits) was overcut in Asia.
