Leyland Cypress…not the best choice

Photo Credit: Ed Gilman, UF/IFAS
Photo Credit: Ed Gilman, UF/IFAS

Leyland cypress, x Cupressocyparis leylandii, has been hugely popular over the past 20 years as an ornamental landscape tree. It has the reputation of being a beautiful evergreen that can grow at a rate of up to 3 to 4 feet per year. Sounds like the perfect option for someone looking to make their back yard more secluded and private. Because of these traits, it has been planted widely throughout the southeastern US, including the Florida panhandle, only to succumb to intense environmental conditions and disease pressure.

UF/IFAS suggests that other species be used in place of Leyland cypress because of the damaging effects of Seiridium canker. The disease is a fungal organism that attacks the tree after periods of drought while the tree is under stress. Once the stress has occurred and rain does arrive the fungus attacks the vulnerable trees in the wetter periods. The major symptom is “flagging” or branches that have turned brown that can be scattered throughout the tree. This is caused by a canker further up the brown branch that has been girdled,cut of from the flow of water and nutrients to the branch by diseased tissue.

Flag branch on Leyland Cypress. Photo Credit: UF/IFAS
Flag branch on Leyland Cypress. Photo Credit: UF/IFAS

What are the options for Florida panhandle landscapers and homeowners? If you have a tree exhibiting symptoms of Seiridium canker, pruning the “flag” branches out several inches below the canker can prolong the life of the tree but is very unlikely to save it. The only long term sustainable option is to replace Leyland cypress with species that are resistant to the disease. The following are good examples of species that could be considered:


Common Name

Scientific Name

Atlantic white cedar

Chamaecyparis thyoides

Southern red cedar

Juniperus silicicola

Arizona cypress

Cupressus arizonica var. glabra

Mexican cypress

Cupressus lusitanica

Oriental arborvitae

Platycladus orientalis

“Green Giant” arborvitae

Thuja x ‘Green Giant’

Kashmir cypress

Cupressus cashmeriana

Chinese funeral cypress

Cupressus funebris

Chinese cypress

Cupressus chengiana

Hinoki cypress

Chamaecyparis obtusa

For more information read the University of Florida publication, Seiridium Canker of Leyland Cypress.



Posted: August 19, 2015

Category: Horticulture
Tags: Disease, Flagging, Fungal Disease, Landscaping, Leyland Cypress, Panhandle Gardening, Seridium Canker, Trees

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