What is wrong with my Leyland cypress?
That has been a popular question at the extension office this spring.
Leyland cypress is one of the most widely used plants in Georgia. It is fast growing and used most often as a hedge or buffer. But they can create problems if not managed properly. Here are some reasons why.
Plant Leyland cypress in well-drained, sunny locations. If the plant has poor drainage, it will be prone to root rot and canker diseases because of their shallow root systems. When planting, space trees at least 8 feet apart; if the trees touch, disease can spread from one tree to another.
Two of the most common diseases are seiridium canker and twig dieback. Seiridium canker symptoms are yellowing or browning of the foliage on one or more top or lateral branches. The discoloration usually appears in spring and is caused by environmental stress, such as drought or overwatering.
If trees are already planted and are showing signs of canker, remove the cankered twigs and branches. Destroy pruned materials and disinfect pruning tools with alcohol or diluted bleach. Unfortunately, fungicides provide no control once the disease has spread.
Planting Leylands in tilled and well drained soils three to four times the size of the root ball will greatly decrease their susceptibility to various canker and root rot diseases.
Another common problem is an insect called bagworm. These worms are disguised in green to brown cone-looking bags, (1 to 3 inches) on the plant. Infestation spreads slowly from one plant to another, and cones are often overlooked because they look like part of the tree and are disguised by their color. Caterpillars remain enclosed within the cone and they hatch in May and larvae feed through July. Bagworms will defoliate a plant and cause limbs to break.
You can get rid of the cones by picking them by hand, destroying the bags after you pick them. Also, Bt, Sevin and any product containing pyrethroids will help to control infestation.
Leyland cypress is a graceful, rapidly growing evergreen. Its height and dense form make it a great hedge or privacy row plant. If you establish new plantings in tilled, well-drained soil with at least 8 feet between each plant, this will reduce problems that might occur.
Wanda Cannon is a Master Gardener trained through the Hall County program and also serves as Master Gardener coordinator and horticulture assistant for the Hall County Extension office. Phone: 770-535-8293.