How to Avoid Drought Stress for Trees
Get tips for keeping trees healthy when water is limited.
During times of drought, homeowners often focus attention on lawns, flowers, ground covers and other plant life that are quick to show the effects of insufficient water, but the landscape fixtures most likely to suffer long-term effects of unavailable or rationed water may not display the impact of drought quite so quickly. Lawns may go dormant, flower beds may be lost, but trees are more difficult to replace and should be the first priority when tending to the home landscape during extended drought conditions.
Signs of stress may not be so obvious and once they are, it may be too late to rescue a tree suffering the effects of severe drought. Slowed growth, a thinning canopy, change in leaf color or needles, dying twigs high in the branches, drooping leaves or premature leaf drop may not have the short-term visual impact of a brown lawn, but a weakened tree may struggle to recover, especially when a tree left susceptible to damage from insects or disease escalates in decline.
When water is at a premium, trees should be the first consideration for homeowners concerned with long-term preservation of the landscape. Trees younger than two years have yet to develop deep root systems and should be given the first sip from the hose, but even well-established trees can be lost to insufficient water. Knowing the best strategies for making the most of the water you have can help to prevent the devastating impact drought can have on trees. Here are a few things you can do to avoid drought stress when the weather is hot and water is limited.
Removing diseased or dead branches is still a good idea, but cutting live branches from a drought-stressed or at-risk tree forces the tree to expend energy healing the wounds, inhibits growth during recovery and exposes the tree to damage from disease or insect attack.
Skip the Fertilizer
Using fertilizer on drought-stressed trees may cause more harm than good. Fertilizer will pull precious water away from tree roots, forces the tree to expend energy trying to process the fertilizer and may even burn roots suffering from water deficiency.
Apply Organic Mulch
Use mulches of leaves, bark or pine needles to a depth of 4 inches to help retain soil moisture. Remove competing turf from around the base of the tree before application and leave a gap of 4-6 inches at the trunk.
Determine Drip Line
The drip line is the ring around a tree where the roots have developed to most efficiently absorb water falling from the canopy of the tree. Focus on this ring reaching the outermost edge of the canopy to make the best use of a limited water supply.
How to Water
Using soaker hoses or a watering wand, water slowly in the critical root zone (about a foot from the trunk to the drip line) to a depth of about 12” to reach the roots most likely to make the best use of the water.
How Much to Water
As a general rule, trees need about ten gallons of water for every inch of diameter of the trunk. Small or immature trees benefit from deep watering weekly and larger trees should be watered twice a month to make the most economical use of rationed water.