Ask The County Agent: ‘Why are my new trees turning brown?’
By Stephanie Butcher, Coweta Extension Office Agent
Question: Help! Most of my newly planted trees are turning brown.
Agent: This is one of the most common calls that I get during the summer. The questions that come with these calls are usually, “What kind of insect or disease is causing this?” and “What should I spray?”
It turns out that 99.9 percent of the cases I see in the summer have nothing to do with insects or diseases at all. You may be surprised to hear this, but too much water is usually to blame. Too much of a good thing, right?
Sometimes we love our plants to death, especially when we experience drought and extremely high temperatures.
While it is true that trees require water, a good rule of thumb for watering trees is an inch of water a week. Soil type has a lot to do with how often you need to water. The soil in our area is primarily heavy clay, and clay can really hold onto water. Many homeowners will often mulch around trees too, which is a good practice to help conserve water, but then they continue to water as much as they were before they mulched. It is easy to overwater this way.
Overwatering can be just as damaging as too little water. It can cause a plant to slowly starve to death. You might see wilting (which can also look like drought stress) and/or yellowing of leaves. Another sign is brownish-colored roots. These roots are unable to absorb water and nutrients. Plants will yellow and begin to look dead.
You can help prevent overwatering by using a rain gauge. Rain gauges can measure water from rainfall or an overhead irrigation system. You can also just use an empty cat food can or tuna fish can. Your plants have received about an inch of water when the can is full.
Checking the soil moisture is also a good way to tell if the plant needs more water. The soil should feel mildly moist. Even if the top of the soil looks dry, it can be moist just a couple of inches down so check to be sure.
Here are some tips to give trees a good start:
Plant trees in late fall or winter. Trees perform better when planted at the right time of year. They can really suffer and show signs of stress when planted in the middle of a brutal, Georgia summer.
Soil test prior to planting. Lime and fertilize prior to planting based on soil test recommendations so that your trees get the proper nutrients.
Choose the right tree for your landscape. Be sure to check the mature size of the tree before you make your choice. You may love southern magnolias, but if you don’t have a large enough area for it, then it will be a problem down the road. Also, don’t plant trees too close to the house or driveway where the root system can cause problems.
Monitor soil moisture and pay attention to sources of water. Don’t plant a tree near a downspout where it can be flooded by too much water.
Don’t make mulch “volcanoes” around the base of your trees. Doing this can cause heat and moisture to build up around the trunk, which can attract insects and create a good environment for disease to develop.
For more information about proper planting and care of trees, email [email protected] or call 770-254-2620 and ask for the UGA publication, Shade & Street Tree Care. The University of Georgia College of Agricultural & Environmental Sciences is an Equal Opportunity, Affirmative Action, Veteran, Disability Institution.