Leyland cypress trees will give you that fast growth if you are looking for a privacy screen or a Christmas tree for your yard, but they are high-maintenance. A hybrid cross between Alaskan cedar and Monterey cypress, the Leyland cypress is classified as an evergreen tree and as a conifer. The plant is named after the person who crossbred the species, Christopher Leyland.
- Botanical Name: Cupressocyparis leylandii
- Common Name: Leyland cypress trees
- Plant Type: Conifer evergreen
- Mature Size: Can grow up to 50 feet tall with a spread of about 1/4 to 1/3 of its height
- Sun Exposure: Full to partial sun
- Soil Type: Clay, loam, and sand
- Soil pH: Acidic, neutral, and alkaline
- Bloom Time: Occasional, if at all
- Flower Color: White
- Hardiness Zones: 6 to 10
- Native Area: North America
Slender and fast-growing at a rate at about 2 to 3 feet per year, Leyland cypress trees are generally grown to meet an urgent need for a mass of evergreen foliage to create a privacy hedge. A needled evergreen, its leaves consist of flattened sprays. Height can vary greatly, depending on the variety and the conditions in which you grow them. For best growth, plant in a full sun site with evenly moist fertilized soil. The average height for an untrimmed Leyland cypress is about 50 feet, but do not be surprised if yours grows much higher or much shorter than that. Taller than they are wide, the spread of this columnar tree is commonly only 1/3 or 1/4 of the height, sometimes less.
Leyland cypress does not tolerate shade well. It grows best in open, sunny conditions and in most soil types, including clay, loam, and sand, acidic, and alkaline. It also tolerates drought and brief waterlogging.
To help its roots get established after spring or summer planting, water your Leyland cypress regularly. A Leyland cypress will take a few months to get established. After that, apply 1 gallon a week to the rootball if you live in USDA zones 7 or 8 and 2 gallons a week if you live in USDA zones 9 or 10. For the first and second years, water your Leyland cypress twice a week through spring and weekly in summer, tapering off to once to twice a month in winter. The older the tree, the longer you can go between waterings. Use soaker hoses, not sprinklers that will wet the foliage.
Leyland cypress trees are best grown in planting zones 6 to 10 with temperature lows of -8 degrees Fahrenheit. However, zone-5 gardeners have been successfully growing them by providing mulch and an A-frame shelter in the winter months to protect them from snow and ice damage. Such sheltering is feasible only while the plants are young—unless you keep them short by pruning. Luckily, once the plants have matured, sheltering becomes unnecessary, as they will prove to be sufficiently cold-hardy in zone 5.
Fertilize Leyland cypress in early spring, before new growth begins. Spread a general-purpose, 10-10-10 fertilizer around the tree's drip line.
Since the tree is a hybrid, it is almost always sterile and propagated mainly from cuttings. Successful rooting is achieved most often with cuttings taken from trees less than 10 years old, or from new shoot growth on older trees. January, February, or March are the best months to do the cutting. Cuttings should be 6 to 8 inches long and show some brown coloration in the lower part of the stem. Dip the end of the stem in a rooting hormone used for woody trees. Plant into a porous planting media. Maintain the cutting in a warm, humid environment. Once the plant develops roots, transplant into a gallon-sized container. After 6 to 9 months, the plant should be ready for planting outside. This is best done in the spring.
Leyland cypress trees are shallow-rooted, meaning they can topple over easily, and they are susceptible to canker, which are dead sections caused by fungus or bacteria, destroy any diseased areas. To deal with canker, clean any pruning tools between each cut to keep it from spreading.
You may also experience infestations of spider mites on this tree. A natural solution for this problem is to spray with neem oil. Another pest that can attack the plant is bagworm; deal with these by picking off the "bags" as soon as you see them.
Their height can be controlled (you can grow them as multi-stemmed shrubs), but only through persistent pruning that starts when the plants are young. Trim the sides of Leyland cypress trees every year in July. After the leader has reached the height you want the tree to retain, make a pruning cut a few inches below that (which will leave room for the vertical growth of minor branches) to preclude any further significant upward growth, as you would do when pollarding a tree.
Use in Landscaping
A common landscape use is planting several Leyland cypresses along a border, in order to create a privacy screen. They are also used as windbreak trees. Since they are amenable to shearing or pruning, some homeowners take this a step further and turn such a border planting into a formal hedge.
Be sure to prune them early and often, otherwise, due to their fast growth rate, they tend to get too tall too quickly and can overwhelm a landscape. In addition to these practical landscaping uses, these plants frequently are used as Christmas trees.