I recently purchased some Green Mountain boxwoods. I made the mistake of leaving them in my car for several hours during the day before removing them later for planting. I believe the plants are heat stressed as the leaves at the top of the plants yellowed. I planted them, provided water, and also a small amount of 13-13-13 fertilizer. I trimmed most of the yellowed leaves, but the plants have continued to yellow, even turning a golden brown in some areas. Any remedies?
The Gardener’s Answer
Hello, Michael: Usually when we see the foliage on boxwoods begin to yellow, this is an indication of nitrogen deficiency, too much water, and other leaf disorders, but if the plants looked healthy when you purchased them I do not suspect any of these are reason for concern. The truth is that it is just a waiting game now. The plants are stressed not only from the extended time period in the hot car but also from being transplanted. For now, continue to remove the foliage that does not look healthy and keep them watered if Mother Nature does not do so. Make sure to dispose of all foliage that you remove, do not leave it on the soil around the plants. Avoid fertilizing them at this time. It really is best to let the plant become established in the environment that exists naturally and then feed them the following year. Keep the soil moderately moist but not sopping wet. A thin layer of mulch no more than 2 inches will help retain the moisture levels and keep the weeds down. Boxwoods are pretty tough plants and if the root system is healthy, more than likely they will be just fine. It will just take them time to recoup and adjust to their new home.