Diagnosing Winter Dieback on Leyland Cypress: Disease vs. Salt Damage

Newly planted Leyland cypresses in a backyard near a main road showed widespread browning after winter. Two likely causes: fungal twig/branch dieback or road salt burn.

How to Tell the Difference

• Salt burn: Worst on road-facing side; needles brown from tips inward.
• Fungal dieback: Random pattern; may have cankers or resin bleeding.

Immediate Actions

1. Prune out dead wood cleanly (sterilize tools between cuts).
2. Apply fungicide if dieback confirmed (spring application).
3. Fertilize moderately to support recovery.
4. Install barrier (burlap screen) if salt is suspected.

Prevention

Ensure good drainage, avoid late-season nitrogen, and water deeply before freeze-up to reduce winter desiccation.