Leyland Cypress Hedge: Topping vs. Tree Form & Disease Risks

John planted 7 Leyland cypresses 4.5 feet apart for privacy. Nursery said to trim sides yearly and top at desired height to maintain tree form. He asked if this works and if spacing was a mistake.

The expert clarified: topping creates a hedge, not a tree form (conical top). At maturity (40 ft tall, 8–12 ft wide), 4.5-foot spacing means they'll merge. Side pruning can control width. Warned of Seiridium and Bot canker (detailed same as previous article). Advised enjoying them until disease appears, then replace if needed.

Hedge vs. Tree

• Topping = hedge (flat top).
• No topping = tree (pointed top).
• 4.5 ft spacing = solid wall eventually.
• Monitor for cankers; replace if severe.