The drought is continuing across the state of Nebraska. This drought has been going on for over 3 years and we are already seeing problems in our plants. These problems will continue to get worse if we don’t have good precipitation through spring and summer this year. 

Drought level

Currently, most of the state of Nebraska is in level D1, Moderate Drought with a large portion in level D2, Severe Drought. There is an area in the panhandle in D3, Extreme Drought. You can find your current drought conditions at droughtmonitor.unl.edu. This map of the current drought conditions is updated every Thursday. 

In level D1, pasture and crop growth is stunted and surface water levels decline. In level D2, crop yields are low, fires increase, roadside haying begins, and well levels drop leading to mandatory surface water restrictions as needed, according to the information found on the drought monitor website. 

Long-term Effects of Drought on Trees

Drought conditions can cause tree leaves to wilt, scorch, or fall prematurely in fall. Drought can also cause branch dieback and possibly death of trees if drought conditions go on too long or are not corrected through irrigation. It is often initially noticed as top dieback in trees. Photo of Drought Stress on a tree to the left is from William Fountain, University of Kentucky, Bugwood.org

Roots are vital to the growth and health of our trees and shrubs. In drought conditions, the root hairs are the first part of the root system to be affected by dry soil conditions (University of Massachusetts Amherst). Dieback of root hairs reduces the water absorbing capacity of a plant. More established and older plants are able to overcome this lack of root hairs over time and as soil moisture is restored; however, newly planted trees suffer most because they already have a reduced root system.

When trees are water stressed, their first response is to close the stomatal openings on the leaves (University of Massachusetts Amherst). This reduces the plant’s ability to bring in carbon dioxide to use for photosynthesis, which is how trees make sugar. 

Other Problems from Drought

There are secondary effects from drought that can affect our plants. Stress on trees and shrubs from drought can reduce their defense mechanisms against disease and insect pressure, causing more problems from these pests. Irrigating will help keep trees healthy and reduce stress.

Another thing we will see in drought situations is an increase in weeds to take moisture and nutrients from trees. It seems odd that other things are dying due to reduced moisture but weeds seem to thrive. Weeds are adaptable allowing them to flourish in conditions where other plants struggle.

Helping Plants through the Drought

Ensure adequate watering throughout the entire growing season for all trees and shrubs, especially those recently planted. Water throughout the winter when soil is not frozen, as necessary. Winter watering should occur around midday on days when the temperature is at least 40-45 degrees Fahrenheit. Test for soil moisture with a long screwdriver prior to watering to determine if watering is needed. If the screwdriver goes into the soil easily, watering is not necessary. However, if pushing the screwdriver into the soil is very difficult, plants should be watered. Always remember to unhook hoses when finished watering in winter months. 

Mulch can also help keep moisture near the plants, the goal is to keep the soil moist, not soggy and not dry. Maintain an even layer of mulch 2-3 inches deep around trees and shrubs to help with drought stress. Mulch can be refreshed anytime throughout the year as needed.