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GARDENING IN GWINNETT: Leyland cypress trees require sufficient space

Timothy Daly

Timothy Daly

One of the most widely planted trees in landscapes across Georgia is the Leyland cypress.

It has many appealing qualities such as its pyramidal shape, attractive dark green foliage, and a rapid growth rate. The tree can be used as a screen to block unwanted views and enhance privacy. Despite its virtues, the plant frequently performs poorly in the landscape as a result of improper planting practices.

Leyland cypress trees can grow 50 to 70 feet high with a spread of 15 to 20 feet. However, they are usually planted too close together. The trees should be at least 10 feet apart, preferably 12 to 15 feet apart, and a minimum of 15 feet away from structures. Planting at this distance doesn’t make them an effective screen for some time.

However, they can grow four feet per year in height and two to three feet in width. In three to five years, they will be effective screens. If waiting a few years is not right for you, the trees can always be planted closer together with the understanding that every other one will have to be removed in time. You can also plant other evergreen plants such as arborvitaes, Japanese cryptomerias, wax myrtles or certain types of hollies as an alternative to the Leyland cypress. They form effective and attractive screens also.

Leyland cypress trees need to be planted in locations that receive full sun. Shade will reduce their vigor and cause the leaves and branches to thin out. The trees require fertile, well-drained soil. One of the most critical factors in the growth of Leyland cypress is making sure they are watered properly. Inadequate amounts and also excessive amounts of water will cause Leyland cypress trees to suffer and decline.

Leyland cypress trees can become infected with a couple of stem canker diseases caused by a fungus. The primary symptom is the foliage on the top or the lateral branches turning yellow or brown. The disease can potentially disfigure or kill the trees. The dry conditions of recent months, in addition to being planted too close to each other, have contributed to the development of these diseases.

Since there are no effective chemicals for control, the best way to treat an infected tree is to prune out the dead branches. Cut below where the canker has formed on the branch and sterilize the pruning tool in alcohol or bleach prior to making the next cut in order to prevent the spread of the disease. If trees that have been extensively damaged or if the trunk itself is infected, they should be cut down. Also, during dry spells, make sure the trees receive the proper amount of water, which will reduce the development of the disease.

Leyland cypress trees can be a great addition to the landscape if properly planted and maintained. However, this tree is rapidly becoming one of the most troublesome trees in the landscape. Due to improper planting and overuse, Leyland cypress may go the way of plants such as the Red Tip Photinia. This small tree was planted extensively in the 1970s and 80s as a hedge, but eventually a fungal leaf spot disease caused many of them to die out.

Timothy Daly is an Agricultural and Natural Resource Extension Agent with Gwinnett County. He can be contacted at 678-377-4010 or tdaly@uga.edu.