Can Leland Cypress Trees Be Trimmed?

Young Hedge Pruning

• In order to maintain Leyland cypress in hedge form, initiate pruning the first year of planting. During the first few years, when trees may grow as much as 3 feet per year, concentrate on trimming only long side shoots. This will encourage denser growth on younger trees. Continue to trim only side shoots until the desired height is obtained. Once the tree reaches this height, trim the leading shoots approximately 6 inches, to allow room for the tree to grow.

Established Hedge Pruning

• Once trees are established as a hedge form, begin to mold plants into an inverted A-shaped wedge. Maintenance of this bottom-heavy form facilitates better light distribution throughout the plant. Bottom portions are likely to turn brown or become bare over time in square-shaped or top-heavy hedges. Avoid cutting more than one-third of the plants height or width at one time. Excessive pruning, down to older leafless portions of the plant can result in hedges with bare patches and exposed wood. Even worse, poor pruning can kill older or weakened Leyland cypress trees.

Pyramidal Form Pruning

• The Leyland cypress is naturally pyramidal in form. Over the past decade, this fast-growing, low-maintenance species has gained popularity among some commercial Christmas tree growers. Pruning practices to encourage this type of growth differ significantly from hedge pruning. To ensure a symmetrical form, remove any double stems or excess leaders within the first year of planting. Continue to remove any double leaders every spring. Tree crown will become increasingly filled out after three or four years, at which point more intense shearing can begin, if necessary. In general, only minor shearing is necessary to maintain an attractive pyramidal form.

Problems

• Relatively few diseases affect Leyland cypress. The most significant problem is canker, which is a highly contagious fungus that seriously disfigures and even kills infected trees. Leyland cypress should not be planted in California, where the problem of canker is most severe. Branch dieback is an indication of disease infestation. Treat infected trees with fungicide. Proper pruning practices can limit the spread of canker. Ideally, prune Leyland cypress only during dry periods.