Grown for their golden foliage and citrusy scent, lemon cypress trees (Cupressus macrocarpa "Goldcrest") brighten the garden. Established lemon cypress trees require little hands-on care or upkeep if grown under suitably bright, humid conditions in U.S. Department of Agriculture plant hardiness zones 7 through 10. Routine maintenance will help them thrive and remain healthy and attractive.
Moisture and Humidity
Lemon cypress trees tolerate moderate drought once established, although they benefit from deep weekly watering during their first season in the ground. Potted plants need regular watering year-round because of their limited root system. Always use pots with drainage holes. Allow the soil to dry out somewhat between waterings to prevent disease. As with all Monterey cypress cultivars, lemon cypresses require moderate humidity to look their best. Those grown in the garden do not need misting because the soil will provide enough humidity, although pot-grown trees benefit from weekly misting during dry weather to keep their foliage healthy.
Established lemon cypress trees do not need fertilizers. Fertilizer can lead to weak growth and destroy the naturally symmetrical growth habit. The only time fertilizing will help lemon cypress trees is when they show signs of nutrient deficiency. If the trees develop stunted foliage or fail to grow, they may need an extra boost of nutrients. A 4- to 6-inch layer of mildly acidic compost spread beneath the drip line of each tree will provide a steady source of nutrients.
Pruning can destroy the natural shape and symmetry of lemon cypress trees, so prune only those grown as a formal hedge and remove only twigs and branches that are obviously out of place. If you find dead branches on your lemon cypress trees, prune them off at the base. Unseasonal discoloration or branch dieback may indicate disease or stress, so wipe the pruning shears clean with rubbing alcohol before and after each use to prevent cross-contamination.
Lemon cypress trees do best in cool, humid climates with a coastal influence and growing them in other areas may lead to problems. Dry, windy weather will dry out the foliage, causing unsightly browning. Misting the foliage occasionally during windy weather will help keep the foliage from drying out and it may also help prevent another, more serious problem known to affect lemon cypresses: cypress canker. True to its name, cypress canker creates weeping, ulcerous sores on the tree's bark, causing irreparable damage to the limb. Prune off affected growth well below the damaged portion using clean, sanitized pruning shears. If cankers form on the main trunk, the tree will have to be destroyed.