What price privacy? Leyland cypress will keep you busy

Q: We would like to plant a privacy screen along two sides of our rural Vashon property and were thinking of planting Leyland cypress, but we don't wish to create a long-term problem for these trees by topping them in the future. That being said, do you think that pruning this species at a height of 12 to 15 feet would be appropriate? Does shearing them to form a loose (or rustic) hedge when they are young seem to harm them? We are trying to achieve some level of privacy without having to resort to the installation of a solid board fence. We have heard that it is very fast-growing and resistant to deer damage.

Does your experience bear this out? Can you think of other options, or do you know of other resources we might contact for information?

A: Cupressocyparis leylandii, a cross between the true and false cypress, may well be the most commonly used hedge tree, and for good reason. It grows quickly (15 to 20 feet in a few years), responds eagerly to shearing, is tolerant of a wide variety of soils and withstands strong winds.

Even Cass Turnbull, of the anti-plant-mutilation organization Plant Amnesty, says, "An exception to the 'no-topping' rule is when a tree is used as a hedge," for if the size of the cuts are small and the trees are tough like these are, they'll survive all the pruning needed to keep them in line.

Turnbull warns, however, that Leyland cypress grow so fast that maintaining them as a hedge is like keeping an elephant in a gerbil cage. She says it is imperative to top (more accurately called "heading") the trees somewhat lower than the intended eventual height, and then shear all the sides and re-head the top each and every year. Constant vigilance is the only way this 125-foot wannabe can be kept hedge-sized.

If you do decide to plant C. leylandii, you might want to seek distinction with the cultivar 'Naylor's Blue,' with foliage toned gray blue; 'Emerald Isle,' which has bright green needles; or 'Castlewellan,' which has golden new growth that warms up a gray day.

The verdict is out on how deer-resistant Leyland cypress may prove; one reference listed them as "rarely damaged" by deer, while another said to avoid planting them anywhere near deer. I'm afraid this means that hungry deer eat pretty much whatever comes to mouth.

To learn all about training and pruning conifers, take a look at the well-illustrated manual "American Horticultural Society Pruning and Training," by Christopher Brickell (DK Publishing, 1996), and watch for Turnbull's own book on pruning due out soon from Sasquatch Books.

There are a great many options for hedging, and you might want to drive around old neighborhoods with established hedges and see which kind captures your fancy. Yew is the traditional English hedge material, with handsome dark green needles that respond beautifully to pruning. Pacific wax myrtle (Myrica californica) and Canada hemlock (Tsuga canadensis) have interesting textures, and the taller species of mahonia or nandina form a wild-looking hedging with the bonus of flowers and berries. Viburnum tinus 'Spring Bouquet' makes a fat, glossy evergreen hedge with fragrant pink flowers from late autumn through spring.

If you want a casual, country look and have enough space, mixed hedgerows planted with a combination of evergreen and deciduous trees and shrubs provide year-round color and interest as well as a perfect thicket for bird habitat. Deer predation wouldn't show up nearly as much with such a loose, soft-edged mixed planting.

"The Sunset Western Garden Book" (Sunset Publishing, 2001) has a list on pages 96 and 97 of plants recommended for hedges and screens. Plus, you're fortunate enough on Vashon Island to have a wonderful nursery like DIG (19028 Vashon Highway S.W.; 206-463-5096), where you can seek the expert advice of proprietress Sylvia Matlock on all things horticultural.

Valerie Easton also writes about Plant Life in Sunday's Pacific Northwest Magazine. Write to her at P.O. Box 70, Seattle, WA 98111 or e-mail planttalk@seattletimes.com with your questions.