Spots on Mountain Laurels

Asked April 18, 2016, 7:57 AM EDT

Hi, I just noticed these spots on all the leaves of my mountain laurels. The trees are over 6 feet tall and mature. They are in partial shade What part of the plant is affected? > Just the leaves Have symptoms progressed or changed? > Getting worse, afraid trees are dying. Growing conditions (full sun, part shade, shade, windy, salt spray, etc.) > Part shade Soil problems (compacted soil, construction activity, poor drainage) > There was a lot of construction over a years ago. Several nearby trees have been removed in that process. Pesticide and fertilizer applications > None Any help you can offer will be greatly appreciated. Regards,

Fairfax County Virginia

3 Responses

Kalmia latifolia, mountain laurel is not an easy shrub to grow. It requires an acid, cool moist, well drained soil in full sun to partial shade but grows best in the shade. When stressed due to environmental or cultural issues such as drought, poor soils, poor drainage, etc. they can be susceptible to insect or disease problems.
Mountain laurel can be susceptible to several leaf spot diseases. Many leaf spot diseases can be tough on the plants but does not kill them. Remove any affected foliage from the ground to prevent any overwintering spores and Remove any old leaves. Make sure mulch is no thicker than two inches in depth and keep away from the stems. If the shrubs are in deep shade you can prune some overhanging tree branches to let in some sunlight. If you want to lower the shrubs, you can prune now to let new growth come in. Water deeply during dry periods if possible. No chemical controls are recommended.
mh

All the leaves have the spot. Won't taking all the leaves off the tree kill it???? Sam

Yes, but we didn't mean to imply you should remove all the leaves from the shrubs!

By "Remove any affected foliage from the ground" and "Remove any old leaves" we meant to rake up and dispose of fallen leaves that lie on the soil. Those infected leaves have spores that can re-infect your plant this year, so you want to get them out of the vicinity.

Sorry for the confusion
ECN