The mountain laurel (Kalmia latifolia), also called American laurel, grows wild in sandy or rocky woodlands throughout the eastern United States. They sometimes grow wild in yards within U.S. Department of Agriculture plant hardiness zones 4 through 9, but cultivars are available at garden centers. This evergreen shrub grows between 5 and 30 feet tall. It usually blooms in May, featuring large clusters of five-sided pink or white blossoms. Overgrown laurels become leggy with no foliage at the base of the plant, and benefit from renovation pruning to encourage new, healthy growth.
Fertilize the laurel well in late fall before pruning in late winter of the following year; well-fertilized plants recover best from hard pruning. Skip this step if the laurel grows in fertile soil and appears to be healthy. No chemical fertilizer is required. Rake back any leaves or mulch from around the base and spread a 1- to 2-inch layer of finished compost or cottonseed meal over the ground. This layer will release nutrients slowly into the ground to feed the roots.
Wash the blades of all pruning tools, and disinfect them in a 10 percent solution of chlorine bleach diluted at a rate of 1 part bleach to nine parts water. Use bypass pruners to cut branches up to 1/2 inch in diameter, lopping shears to cut branches up to 1 1/2 inches in diameter, and a pruning saw to cut larger branches.
Remove one-third of the total branches in late winter around February or early March. Cut the branches to within 6 to 12 inches of the ground; this severe, renovation pruning encourages new branches to grow from the base. Remove all broken, diseased and dead wood first, then move on to the older wood if needed, until you have removed one-third of the branches. Use lopping shears or a pruning saw, depending on the thickness of the branches.
Apply fertilizer again in late fall, one year after the first fertilizer application.
Cut another one-third of the old laurel branches to within 6 to 12 inches of the ground. Start with the dead, diseased and broken branches. Remove the oldest branches, as well as any rubbing or crossing branches. Continue pruning branches selectively until you have removed another one-third of the old branches, leaving the final one-third on the laurel to be removed the next year.
Apply the finished compost or cottonseed meal fertilizer again in late fall, two years after the first fertilizer application.
Remove the remaining one-third of the old laurel branches to within 6 to 12 inches of the ground. The plant should have some new branches now, but it can take some plants up to five years to recover from renovation pruning.
Deadhead laurel flowers as they fade each year to prevent the plant from going to seed and to extend the blooming period. You can use bypass pruners to cut behind the flower clusters, or pull them off with your fingers.
Prune back the tips of long branches to control the height and shape of the mountain laurel bush. Wait until the end of the blooming period, usually in June, to trim the branches. Make an angled cut just above a leaf set or node on the branch. Remove no more than one-third of the total branch length each year.