Leyland Cypress is a fast growing columnar evergreen tree most often used for screening. Once established, it can grow three to four feet in a year. Its ultimate height is 60 – 70 feet with a spread of 8 to 10 feet. It is critical to be aware of the tree’s requirements so that it will grow to maturity. Leylands require full sun and adequate drainage, and should be planted 8 to 10 feet apart for good air circulation. The majority of nutrient absorbing roots exist in the upper 12 to 16 inches of the soil. Large trees require a minimum of 200 to 400 square feet of rooting area.

The tree has a thin bark which splits easily when temperatures are high and the soil is dry. Cold injury caused in winter when temperatures are less than thirty degrees at night followed by a daytime temperature in the sixties also cause the bark to split. Leylands are susceptible to several fungal problems which invade the tree at these cracks, wounds and natural openings.

  SEIRIDIUM BOT CANKER
Fungus Seididium unicorne Botryosphaeria dothidea
Vector Wind, Water from rain & irrigation distribute spores. Wind, Water from rain & irrigation distribute spores.
Entrance to tree Wound, cracks, lenticles (natural openings) Wound, cracks, lenticles (natural openings)
Prime Season Early Spring Spring and Summer
Symptoms – Initial Small black dots barely visible to naked eye, Spore causes canker which discolors cambium tissue.
Symptoms – Primary Sap oozing from entry point. Sunken reddish, dark brown purplish cankers form on stems, branches, branch axils. Cambium layer red/brown color. Bright, rust colored branches and yellowing or browning of shoots and branches. Diseased needles do not fall off. Little or no sap ooze.
Symptoms – Within one year Dieback of foliage above canker. Needles will fall off. Sunken, girdling canker at base of dead shoot or branch.
Symptoms – Year(s) Later Much of tree dead. Large cankers on trunk. Tree dying.
Controls – Chemical None once infection takes place. None once infection takes place.
Controls – Pruning Prune 6 inches below canker. Disinfect tools after each cut. Prune 6 inches below canker. Disinfect tools after each cut.
Prevention Keep properly irrigated during periods of drought. Keep properly irrigated during periods of drought.
Prevention Avoid injury during planting or working around Leylands. Avoid injury during planting or working around Leylands.
Prevention Ensure sufficient air circulation and sunlight. Ensure sufficient air circulation and sunlight.
Prevention Destroy infected and pruned materials. Destroy infected and pruned materials.
Prevention Mulch several feet beyond lowest limbs. Mulch several feet beyond lowest limbs.

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