Using Leyland Cypress Tree in Your Landscape

A rapidly-growing evergreen when young, Leyland Cypress will easily grow three to four feet per year, even on poor soils, and can ultimately attain a height of some 50 feet. The tree forms a dense, oval or pyramidal outline when left unpruned, but the graceful, slightly pendulous branches will tolerate severe trimming to create a formal hedge, screen or windbreak.

The tree quickly outgrows its space in small landscapes and is too big for most residential landscapes unless regularly trimmed. Unusually, shallow roots of the species can give in wet soil to topple large trees.

Uses

• Scientific name: x Cupressocyparis leylandii
• Pronunciation: x koo-press-so-SIP-air-iss lay-LAN-dee-eye
• Common name: Leyland Cypress
• Family: Cupressaceae
• USDA hardiness zones: 6 through 10A
• Origin: not native to North America
• Uses: hedge; recommended for buffer strips around parking lots or for median strip plantings in the highway; screen; specimen; Christmas tree
• Availability: generally available in many areas within its hardiness range

Form

• Height: 35 to 50 feet
• Spread: 15 to 25 feet
• Crown uniformity: symmetrical canopy with a regular (or smooth) outline and individuals have more or less identical crown forms
• Crown shape: columnar; oval; pyramidal
• Crown density: dense
• Growth rate: fast
• Texture: fine

Foliage

• Leaf arrangement: opposite/subopposite
• Leaf type: simple
• Leaf margin: entire
• Leaf shape: scale-like
• Leaf venation: none, or difficult to see
• Leaf type and persistence: evergreen
• Leaf-blade length: less than 2 inches
• Leaf color: blue or blue-green; green
• Fall color: no fall color change
• Fall characteristic: not showy

Structure

• Trunk/bark/branches: grow mostly upright and will not droop; not particularly showy; should be grown with a single leader; no thorns
• Pruning requirement: needs little pruning to develop a strong structure
• Breakage: resistant
• Current year twig color: green

Planting

Leyland cypress trees enjoy both part shade/part sun and full sun—the tree has very forgiving light requirements. The cypress can be planted in many soils. The tree tolerates clay, loam, sand and will grow in both acidic and alkaline soils but still needs to be planted in a well-drained site. It tolerates drought conditions and is salt tolerant.

When planting Leyland cypress, remember the tree's mature size and fast growth rate. Planting a cypress too close is not recommended. You will be tempted to plant the seedlings too close but ten-foot spacings should be a minimum in most landscapes.

Pruning

Leyland Cypress is a fast grower and, if not pruned early, can get out of hand as a hedge. In the first year trim back long side shoots at the start of the growing season. Trim sides lightly in late July. The sides can be trimmed the following to year encourage denser growth. Continue to trim the sides each year leaving the leading shoot untouched until the desired height is reached. Topping and regular trimming of the sides should prevent trees from becoming increasingly large.

Seiridium Canker

Seiridium canker disease, also called coryneum canker is a slow-spreading fungal disease of Leyland cypress. It disfigures and damages trees, particularly in hedges and screens that are heavily pruned.

Seiridium canker is usually localized on individual limbs. The limb is usually dry, dead, often discolored, with a sunken or cracked area surrounded by living tissue. You should always destroy diseased plant parts and try to avoid physical damage to plants.

Sanitize pruning tools between each cut by dipping in rubbing alcohol or in a solution of chlorine bleach and water. Chemical control has proven to be difficult.

Horticulturist Commentary

Dr. Mike Dirr says about Leyland Cypress:

"...it should be restrained at an early age before pruning becomes impossible."

Additional Information

Leyland Cypress grows in full sun on a wide range of soils, from acid to alkaline, but looks its best on moderately fertile soil with sufficient moisture. It is surprisingly tolerant of severe pruning, recovering nicely from even severe topping (although this is not recommended), even when half the top is removed. It grows well in clay soil and tolerates poor drainage for a short period of time. It also is very tolerant of salt spray.

Some available cultivars include: ‘Castlewellan’, a more compact form with gold-tipped leaves, excellent for hedges in cool climates; ‘Leighton Green’, dense branching with dark green foliage, columnar form; ‘Haggerston Gray’, loose branches, columnarpyramidal, upturned at ends, sage-green color; ‘Naylor’s Blue’, blue-grey foliage, columnar form; ‘Silver Dust’, wide-spreading form with blue-green foliage marked with white variegations. Propagation is by cuttings from side growths.