Reconsider Planting Leyland Cypress in Your Yard

Seiridium on Leyland Cypress
Seiridium on Leyland Cypress. Steve Nix

The rapidly-growing Leyland cypress tree or Cupressocyparis leylandii quickly outgrows its space in a typical yard unless properly and regularly trimmed. They have a potential to grow to 60 feet and not a practical tree to plant as a small yard hedge on tight 6 to 8-foot centers. Tight spacing of the plant means that you must commit major time and effort by constantly pruning.

Another thing to consider: Leyland cypress is a short-lived conifer, only living for twenty to twenty-five years and will eventually have to be removed. I've found that even properly spaced trees left to quickly grow large may have limited root support and are subject to blow down during high winds on wet soils. You should consider the work needed to maintain a Leyland cypress before planting.

Consider the Environment in Which You Plant Leyland Cypress

A study of Leyland cypress done at the University of Tennessee indicated that a lot of the damage is simply environmental and it is not directly caused by a disease or insect. The study indicated that stress from a harsh winter can cause "sporadic limb die off".

As I have already mentioned, these cypresses grow into large mature trees at 60+ feet tall with a potential 20+ feet spread. When they are planted as hedges on tight centers less than 10 feet, you will see a major competitive struggle for nutrients and shading. When you see needles that have browned out or dropped toward the inside of the plant or in areas that receive shading, the tree is reacting to these environmental stresses.

Leyland Cypress trees do not tolerate many diseases and insects well, especially when environmental stressors are present. The way you space these trees and where they are planted can provide an environment that could cause future tree stresses. Planting them too close together and too close to other trees or structures that shade them can decrease vigor and increase pest damage.

What to Do When You Have Already Planted Leyland Cypress

Eliminating moisture stress by watering can help lessen the occurrence of the canker diseases they are susceptible to. In particular, you need to know that the cypress is very susceptible to Seiridium canker. There is no control for this disease other than to prune out the infected plant part.

So understanding that water is extremely important for these trees, you will need to provide moisture for as long as you have this plant. Watering should be a long-term commitment for the Leyland cypress owner. They should be watered during any period of dry weather and should receive at least 1” of water per week. Make sure you place the water at the base and do not spray water on the foliage with sprinklers that can incubate tree disease.

As these tree age and lose lower foliage, you might consider removing each individually as they deteriorate and replace with a deciduous evergreen tree like wax-myrtle or a more appropriate conifer.

Redeeming Features:

*Leyland cypress is a handsome plant with Christmas tree-like qualities.
*Leyland cypress can put on three feet of growth per year on a good site.