One problem involves over-applications of herbicides to a lawn in which the tree roots reside, or even to a gravel or bare area that the trees are near. Since herbicides don’t know the difference between a broad-leaf weed and a broad-leaf tree or shrub, you can get leaf browning, leaves dropping and plants looking poor. However, when herbicides have been used you will often see other signs, such as leaves cupping, which is where the leaf edges thicken and draw the leaf into a cup shape. Sometimes there is distortion of the leaf as it’s growing, or there could be unusual discolorations of the leaves. As such, it’s always best to follow label directions and avoid over-applying any chemical.
Another reason leaves or leaf edges turn brown is because of over-application of fertilizers. The same holds true here, in that you should follow label directions and don’t over-apply fertilizers. Generally speaking, it’s rare that ornamental trees need fertilizers applied for them specifically. Usually what is applied to a lawn or other plants in the area allows the tree roots to find all the nutrients they need as long as those roots can grow properly.
Finally, the most common reason, which is also the easiest to correct but seems the most difficult to get across to people, is inadequate watering. As plants grow larger their roots spread out and their water needs increase. This is where understanding the root growth of your plants helps in meeting water needs. Also, with the lack of good rainfall, which means one-half inch or more per episode, the soils, especially eight to 10 inches or deeper, are often really dry. If you are always only doing shallow watering you may be helping your lawn and other plants, but at the expense of your trees and larger shrubs.
Lawn issues are typical for this time of year, and many people are experiencing spots forming in lawns that involve the majority of the following issues:
If the spot where the grass died out is smaller, say four to six inches or so across, and the spot doesn’t enlarge but starts to green up after a week or so, the problem was most likely caused by an animal taking a bathroom break.
Should the grass die out in a spot and then areas near it start dying and enlarging, it’s likely white grubs. But the problem could also could be billbugs, which are much rarer. If you start seeing holes dug in the grass you probably do have grubs, and skunks are digging them up.
Another problem can occur when you don’t bag your grass and the lawn feels a bit spongy, but not from watering. Should a large area brown out fairly quickly but then slowly start growing back, it’s likely you have a lot of thatch – partially decayed plant matter. As such, it’s likely that the roots of your lawn are partially growing in the thatch, which can cause a fungus. The fungus is not the real problem, though. Rather, you need to get rid of the thatch.
The last main reason for brown spots in lawns revolves around compaction of the soil, so try not to put heavy objects on your lawn, such as your vehicle, and when possible, do a core aeration at least once a year.
Thought for the day: “Love the trees until their leaves fall off, then encourage them to try again next year.” —Chad Sugg.
For more information about these topics call the Utah State University Extension Grand County office at 435-259-7558 or email Mike Johnson at firstname.lastname@example.org.