We have been experiencing hotter and dryer than normal weather conditions this summer which can have a significant and lasting damage on plants in the landscape. Plants and trees draw in moisture from the soil using it for plant growth then release water through the stems and leaves through “transpiration.” When the rate of transpiration is greater than the amount of water plants are drawing in, we begin to see the signs of drought stress. The timing of these drought conditions is equally as important as more damage can occur during the longer days during June and July versus August and September. Knowing some of the best practices for managing plants in the landscape during these drought conditions can save plants from severe damage or death.
Check for drought stress on a regular basis. Symptoms may include wilting, yellowing and browning on the edges of leaves, defoliation and dieback. In extended drought conditions leaves may be smaller and possibly defoliate.
Gather information about the plants and determine which plants in the landscape have the highest water needs, replacement costs and aesthetic value. The highest priority should go to young trees and shrubs that have recently been planted. Large, mature trees should be able to tolerate temporary drought conditions, but may require watering if the drought becomes severe. Medium priority plants should include perennials, fruit and nut trees, small fruits and vegetables and young turf. Lower priority plants include annuals, herbs, ornamental grasses and established turf.
Tall turf-type fescue lawns should be able to withstand drought conditions and do not have to be irrigated. Along with fescue, blue grass being a cool season grass will brown out and go dormant returning to green with cooler and wetter weather. It is a good idea to increase the height on the mower to 2.5-3” when mowing these types of grasses. Zoysia and Bermuda grass also require very little maintenance during drought conditions.
Begin watering at the first sign of stress. The best way to water landscape plants is deeply and slowly so the water soaks down to the roots. Watering in the morning is ideal as it helps prevent disease. Water the plants so at least the top 6 inches of soil are wet. It is important to water at the root zone of the plant and remember the larger the plant the larger the root zone.
Be sure to mulch around plants (2-3” deep) as that will create moisture and keep the plant roots cool. Avoid pruning plants during drought conditions. Pruning opens up canopies causing sun scald on plants. Avoid using fertilizers and pesticides as they can damage the plant’s root system and burn the foliage.