Asked April 17, 2019, 6:56 PM EDT

Please see attached photos. Not sure what is going on with these boxwoods, but I suspect overwatering. There is a sprinkling system in that area, and I believe the school had them on too much. The boxwoods are turning brown and do not look healthy at all. At first I suspected winter damage/burn, but last year these shrubs were gorgeous and the only thing that has changed is the water situation. I feared boxwood blight, but not really sure. I know it's hard when looking at pictures, but do you think these shrubs might come back? Any advice is greatly appreciated. Thank you!

Oakland County Michigan

1 Response

I'm assuming these pictures were taken this (early) spring? Winter damage from cold and ice cannot be ruled out because we had several severe ice storms, which can wreak havoc on evergreen stems of boxwoods.

If these boxwoods are located where they get salt spray from a road or other salted area, or if they are open to cold winter winds, they will be damaged from the effects of the salt and cold. Please see information in the link below.

A third possibility, but I believe unlikely in your case, is boxwood blight, which has now been found in Oakland County in Michigan as of December, 2018. Some easily discernible symptoms of blight are brown fungal spots on the leaves and rapid browning. The spots would occur prior to the leaves dying and turning brown. If you suspect you have boxwood blight, you should contact your local MSU Extension office. They may suggest you send a sample into the MSU diagnostic lab for a positive ID. Please see the information in the links below:

BI also would doubt that the boxwoods were overwatered. Boxwoods should be planted in a partial shade location with well-draining, slightly acidic to slightly alkaline soil. Boxwood shrubs also need wind screens to protect them from high winds or dry winter winds. Whether or not a dry boxwood can be saved depends on the reason it is dry. Here are some steps you can take to try to rejuvenate your boxwoods:

Water the boxwood just enough to keep the soil moist. Soak the soil each watering so you can go longer between waterings. Boxwood plants are shallow-rooted, so if the soil dries deeper than one inch, it may mean the shrub is not getting enough moisture.

Add a 1-inch layer of mulch over the root zone of the shrub to help retain soil moisture. Keep mulch at least six inches away from the base of the shrub.

Prune out any dead or diseased branches with shears, cutting back to just outside a set of leaves. Check the cut to see if the wood is healthy and green, dry or streaked with brown. If the wood is healthy, the shrub will recover. If not, cut back farther until you reach healthy wood or remove the entire branch. Boxwoods accept pruning readily.

Remove old leaves or debris that accumulate in the center of the shrub or around the base. This will help prevent the growth of disease-causing fungus or bacteria.

Thin the center of the shrub yearly to facilitate air movement and keep the shrub healthy. Choose several 4- to 6-inch long branches to remove from the center of the boxwood. Remove about 10 percent of the inner branches, or thin until you can easily see the interior branch structure.

Place a sun screen near the plant if the leaves are drying because the afternoon sun burns them.