My Mountain Laurel Plant Is Growing Sparse

Shrub Habit

• A wild mountain laurel growing in its native range of the higher elevations around the Appalachian Mountains grows 7 to 15 feet tall. Garden cultivars often mature much smaller with more compact branching. When grown in full sun, mountain laurel is more rounded and dense, but becomes open and architecturally picturesque with more shade in the landscape. Too much shade inhibits flowering, and the plant becomes weak and leggy.

Pruning Insight

• Since mountain laurels are generally slow-growing, gardeners rarely prune the shrubs unless a dead branch occurs. The larger the shrub, the more beautiful it becomes, so any tip pruning is avoided to encourage as much growth and size as possible each year. Any light trimming is done immediately after flowering ends. If a mountain laurel gets scrawny or lop-sided, or loses vigor after being very old, harsh pruning leads to rejuvenation. As long as plants are healthy and are not stressed with drought or low soil nutrition after pruning, the mountain laurel grows with an improved habit.

How to Rejuvenate

• In very late winter or early spring, cut back a leggy or old, scraggly mountain laurel for rejuvenation. Cut back all branches to 2 to 4 feet tall, or as low as 2 inches if the shrub already is quite small. New growth sprouts from dormant buds below the pruning wounds over the summer. A fuller, dense shrub that once again flowers heavily occurs two to three years later.

Keeping Plants Healthy

• Prevent new growth on mountain laurels from being too sparse and scrawny by planting the shrubs where they receive no less than four hours of direct sun rays any time of day. Mulch the soil with acid-forming matter such as pine bark or needles. The mulch keeps the soil cool, moist and full of nutrients to support the strongest branch, leaf and flower development. Apply a slow-release granular rhododendron fertilizer according to label directions to ensure the soil remains fertile. Irrigate during drought to prevent branch dieback or leaf yellowing and premature drop.