Drought toll on lawns and trees
The start of our third year of drought coupled with some abnormally hot temperatures in the past three to four weeks has put a great amount of stress on lawns, trees and shrubs. One does not have to look far to see many examples of this stress. There are some things that you can do to help your landscape to survive and maintain an acceptable level of health.
Lawns with large browning spots in them are increasingly common. Much of this is drought stress, although there is also evidence of white grub damage on certain lawns. But the drought stress is by far and away the most common. All our lawns are cool season grasses, and the extreme heat coupled with dry conditions has sent many lawns into dormancy. This is the natural way that cool season grasses react and survive these conditions. If left alone, they will remain dormant until more normal rainfall and temperature returns.
If you want to keep you lawn looking nice, or want to revive a stress dormant lawn, watering can help. Watering should be done weekly. At least 1 inch of water should be applied to the lawn, split into two half-inch watering’s about three days apart. By putting on at least a half inch at a time, the water goes deeper into the soil. This encourages the grass to root deeper to access this moisture and will help it stay green and healthy. Place a rain gauge or a straight sided container in the sprinkler pattern to know when half-inch has been applied. Don’t go by guess and by gosh as underwatering is more damaging to a lawn than no watering.
Trees and shrubs are also showing the effects of the drought. Even older, established trees are showing thinning leaf canopies, reduced growth, and dried, browning leaf edges. Young trees are showing the most injury. Whole branches, tops and sections of these trees will be leafless. Leaves may be “firing off” or turning brown and hanging on the trees. All are signs of being too dry.
With trees, the first step is to get rid of any grass growing close to the trunk of the tree. Either spray out with a grass specific herbicide or with a glyphosate herbicide which will kill all vegetation growing around the tree. Be sure to read and heed the label on use of you herbicide. Take care to keep the glyphosate off of green tree bark and leaves.
The second step is to place wood mulch around the tree where the grass was killed. This will help to conserve moisture, reduce weed growth, and will keep the ground and the roots in it cooler. This will also protect the tree from mower and weed whip injury. Make the grass free area at least 3 feet all around the tree to give it a good chance to recover and grow. “Bigger is better” definitely applies to the size of the mulched areas under a tree. The tree will respond with faster growth and improved overall health because of mulching.
To make the tree mulching more attractive, perennial flowers can be planted in the mulch. They do not take enough water to over compete with the tree for moisture. It will add interest and beauty to your landscape if you plant some perennials around your trees.
The third step is to water the tree slow and deep. Water out closer to the tips of the branches where the feeder roots are located. There are almost no feeder roots right by the trunk. Let the water run so that it soaks in deep all around the tree. Don’t add additional fertilizer at this time. Wait until rainfall returns to normal before doing so. Let the tree respond as naturally as possible so that it is adapted better to the current conditions. Trying to encourage more growth with fertilizer in a drought can cause problems.
It will take a few years of average rainfall and snowmelt before the trees return to normal. What we are trying to do is to maintain them in as good of health as we can. Don’t be disappointed in slow or no growth. It is the tree’s way of adjusting to the current growing conditions.