Troubleshooting
Leyland Cypress problems — and how to fix them
Leyland Cypress (× Cuprocyparis leylandii) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Cypress aphid
Causes brown, dead patches that rarely re-green; inspect in spring and treat early, as bare patches on old wood do not regrow.
Outgrowing its space
Untrimmed plants reach 20 m+ fast and shade neighbours; trim 2-3 times a year and never cut back into bare brown wood, which won't reshoot.
Coryneum / Phytophthora canker
Resin bleeding and dieback of branches, worse on stressed or waterlogged trees; remove affected limbs and improve drainage.
Root rot in wet soil
Yellowing and whole-tree decline on poorly drained sites; plant only where water moves freely away.
Prevent leyland cypress problems before they start
Most leyland cypress issues are care-mismatch, not bad luck. Dial in the basics:
Looking for leyland cypress in general rather than its problems? Read the full leyland cypress care guide — light, water, soil and feeding.
Leyland Cypress problems — FAQ
Why is my leyland cypress cypress aphid?
Causes brown, dead patches that rarely re-green; inspect in spring and treat early, as bare patches on old wood do not regrow.
Why is my leyland cypress outgrowing its space?
Untrimmed plants reach 20 m+ fast and shade neighbours; trim 2-3 times a year and never cut back into bare brown wood, which won't reshoot.
Why is my leyland cypress coryneum / phytophthora canker?
Resin bleeding and dieback of branches, worse on stressed or waterlogged trees; remove affected limbs and improve drainage.
Why is my leyland cypress root rot in wet soil?
Yellowing and whole-tree decline on poorly drained sites; plant only where water moves freely away.