Q. I’ve noticed during my nightly walks through town that many people have brown, dead sections on their bushes and shrubs. How did this happen, and what should be done to the dead spots, if anything?
A. Most of those brown spots, especially on evergreens, probably occurred as a result of our horrendous weather last winter. A combination of wind, sun, and extremely dry air can cause foliage to turn brown. It is a process called desiccation, which in layman’s terms is essentially Mother Nature sucking all of the moisture out of the plant. You think your skin felt dry last winter? Imagine how your plants felt.
If (and it’s hard to know for sure) winter desiccation was the cause of your damage, the best way to avoid it is to wrap the plant in burlap in late fall to protect it from winter damage. Although it is unattractive, it may be something you want to consider doing this fall to prevent further damage. The current projection for the upcoming winter is that it will be as bad, if not worse, than last winter. Sigh.
Other Causes of Browning
•The plant may be infested with aphids. If you see small, soft body insects in the plant, you should spray with an insecticidal soap.
•The plant may be infested with spider mites. Are there tiny webs in the plant? Use a pesticide specifically formulated for mites.
•The plant may be succumbing to fungal disease. If you notice tiny black spots, remove the infected branches to avoid spreading the disease further. Spray with an antifungal spray.
•Insufficient moisture. Not enough rainfall to provide moisture for the plant? Water on a regular basis (at least every two weeks).
•Dog urine. If your bushes are close to an area where dogs like to “lift their leg” you might consider using some form of dog repellant to keep animals from urinating on your bushes.
•Salt damage. If your bushes are close to the road, they were most likely sprayed with salty slush from the snow plow.
When you first notice damage in the spring, we recommend against pruning right away to see if the plant will recover. But let’s be real. It’s August, so it’s pretty evident that the plant is not going to recover in the damaged areas. The damage is now permanent and you need to care for the plant as best you can.
What to do?
If green growth does re-emerge on the brown branch, prune the branch back as far as the green section and stop. But if there is no green, then prune it off entirely. A dead branch on a tree will never come back to life, so just prune it out and allow the tree to refill itself in that spot. In the beginning, it may look like Leatherface (Texas Chainsaw dude) went all slasher on your plants. Sort of like when I tried to cut my son’s hair with the clippers when he was a kid. Fortunately for you (and me), branches, like hair, will regrow in pruned out locations.
If sunlight can reach into that spot, a tree or bush will invest in new branches if it can get a return in the form of photosynthesis. Unfortunately, if the spot is in a shaded area, it will probably not send out new branches or leaves.