The Leyland cypress (× Cuprocyparis leylandii) is a popular choice for hedges and screens due to its rapid growth and dense foliage. However, without regular pruning, it can quickly grow out of control, making maintenance difficult and expensive. Unchecked growth can overshadow gardens, dry out surrounding soil, and impede the growth of other plants. This guide provides essential tips for pruning and maintaining Leyland cypress, as well as other similar conifers like Chamaecyparis lawsoniana (Lawson cypress) and Cupressus macrocarpa (Monterey cypress).
When to Prune Leyland Cypress
Pruning is best done during the growing season, from April to the end of August. Up to three trims can be carried out in this period to maintain the hedge’s shape and health. Before pruning, always check for bird nests, as it is illegal under the Wildlife & Countryside Act 1981 to disturb or destroy nests that are in use or under construction.
How to Prune Leyland Cypress
Formative Pruning for Young Hedges
- Year One:
- In April, trim back long side shoots to promote bushy growth.
- Lightly trim sides in July and tie the central leader (main vertical shoot) to a supporting cane for a straight, dense growth habit.
- Second Year:
- Continue trimming side shoots to encourage density and ensure a tidy winter appearance.
- Subsequent Years:
- Regularly trim side shoots but leave the top untouched until the hedge reaches the desired height.
- Once Desired Height is Achieved:
- In spring, shorten the leading shoots by 15 cm (6 inches) below the final desired height. Allow new growth to fill in, creating a thick and even top.
Pruning Established Hedges
- Trim both the top and sides up to three times during the growing season.
- Shape the hedge into an inverted wedge (A-shape) with a wide base. This design ensures all parts of the hedge receive adequate sunlight, preventing the base from turning brown or bare.
Managing Overgrown Hedges
- Overgrown Leyland cypress hedges can be reduced by up to one-third of their height in early April, just before new growth begins.
- Avoid cutting too much off the top, as this may lead to a flat, bare-topped hedge or even plant death, especially in older or less vigorous specimens.
- For more significant reductions:
- Reduce by one-third initially.
- Allow the plant to recover before making further reductions.
- When reducing width, avoid cutting into bare, older wood as it does not regenerate new growth.
High Hedges and Legal Considerations
Leyland cypress hedges can grow to towering heights if left unchecked, often causing disputes between neighbors. The Anti-Social Behaviour Act 2003 (Part 8) provides a legal framework to resolve issues arising from overbearing high hedges. This law, effective since 2005, allows individuals to address issues without resorting to costly legal action, ensuring fair resolutions for affected parties.
Common Problems
- Brown Patches:
- Occur when trimming cuts into older, leafless growth or when pruning is carried out outside the growing season. Avoid cutting into bare wood to prevent unsightly patches.
- Pests:
- Infestations of cypress aphids can cause extensive browning. Monitor hedges regularly and treat infestations promptly.
- Skin Irritations:
- Leyland cypress sap can cause irritation. Wear gloves and protective clothing when handling.
By following these guidelines, you can maintain healthy, well-shaped Leyland cypress hedges that enhance your garden’s aesthetic without causing excessive shading or neighborly disputes. Regular pruning ensures dense, attractive growth and prevents your hedge from becoming a nuisance.