Since I have been the Agriculture and Natural Resources agent for Barton County, my columns have centered on the drought, and how you can water effectively to help your plants through the stressful times. Well, now the pendulum has swung the other direction, and many are wondering how all of this water will affect their plants. I found a couple of short columns from Ward Upham, KSRE Horticulture expert on a few water issues that are on many people’s minds.
Leaves Turning Yellow or Red:
In Kansas we often see chlorosis (yellowing) of plant leaves due to high pH soils making iron unavailable. However, there can other causes that result in similar symptoms. For example, we have received so much rain in certain parts of the state recently that plants are unable to take up the nutrients needed to maintain a good green color. The cause of this condition is actually a lack of oxygen in the soil due to soil pore space being filled with water. This lack of oxygen to the roots often results in a yellowing of foliage. In certain plants such as oaks and maples, however, it may also lead to a reddening of some of the newer leaves.  
Fortunately, color changes due to wet soils will be corrected as soils dry. Plants should regain their color when we return to more normal weather.
Trees Shedding Leaves:
If trees shed leaves in a general shedding with all parts of the tree losing some leaves, then there is no cause for concern.  A general shedding of the leaves is most often due to weather turning hot and dry. The tree drops leaves because the root system can no longer keep up. Dropping leaves helps balance the amount of water available from the root system and the amount needed by the leaves.
However, the same thing can happen if the soil is too wet. A lack of oxygen in the soil compromises the root system so it can no longer
support all the leaves. Therefore, the tree drops some leaves to bring the tree roots and leaves back into balance. The tree will retain more than enough leaves to remain healthy.
What do you do when the lawn can’t be cut because of constant rain?
The best thing to do is to set your mower as high as possible and bring it down in steps. It is always best never to take more than one third of the grass blade off at one time. If more is taken, the plant reacts by using stored energy reserves to quickly send up new growth. This reduces the amount of energy available for the plant to deal with stress or damage done by insects or disease. However, sometimes it is just not possible to keep the “one-third rule.” In such cases, cut as high as possible even though it may mean you are cutting off more than one third of the blade. Bring the height down gradually by cutting more often and at progressively lower heights until you reach the target height.
Alicia Boor is the Agriculture and Natural Resources agent for Barton County K-state Research and Extension. One can contact her by email at aboor@ksu.edu or calling 620-793-1910