Fall Watering

Fall is here but don’t put those garden hoses away! Cooler temps and change of season doesn’t mean the drought is over. Once again, we are entering the fall dry and this will impact the health of our landscape plants. Perennials, trees, and shrubs need watered infrequently but deeply. Lawn irrigation systems are not designed to deliver this kind of water. Water slowly to reduce run off and allow peculation to about 8” to 12”. Measure the progress of the water with a long screwdriver or dowel rod.

Turf grass is often the trees biggest competitor. With small rain events turf will often capture the moisture before it is able to reach the roots of trees and shrubs. “Since turf grass has a dense root system concentrated in the upper 2-6 inches of soil, it is able to out compete trees when the rainstorm does not thoroughly saturate the soil profile.” Illinois Extension. Furthermore, ”with respect to influence on plant growth and health, it is the amount and frequency of rainfall received during the growing season that is of greater significance than the total amount of precipitation in a given year.” Ron Kujawski from University of Massachusetts. A large rain event will help improve our yearly annual total of moisture but often falls short on solving or improving plant health.

What can we expect with tree health? Trees will be stressed. This stress can allow minor issues to expand into major problems. We are starting to see short term effects of drought manifesting in our landscape. Trees are starting to defoliate early and showing signs of scorch. Long term damage will show up by canopy decline, branch dieback, and plant death. We saw this when river birch trees failed to leaf out in the top 1/3 to 1/2 of the canopy this spring.

Water your trees.