Water stress in trees and shrubs
damaging over the long term
The symptoms of too much or too little water are similar when it comes to trees and shrubs.
Symptoms that a tree has too little water:
- Yellowing or wilting leaves.
- Leaves are scorched on the edges.
- Some trees develop early fall colour and may drop some or all of their leaves prematurely.
- More severe symptoms are a thinning of the canopy, branch dieback or early death.
Symptoms of too much water:
- Yellowing or wilting leaves.
- Saturated soil causes roots to suffocate, die and rot.
- Small leaves, stunted growth and eventual decline of the tree follow.
In both cases, water stress opens the tree to insect and disease. Look at the history and topography of the site to decide if too much or too little water is the cause of your symptoms.
- Historical weather. A dry, hot summer or recent overland flooding may be obvious but weather patterns prior to the current years’ growth may also be a factor. A warm fall and winter with little snow cover, a high water table and searing wind may contribute to water stress, whether too wet or too dry.
Determine if water saturating the area as a result of:
- extreme weather
- low-lying landscape
- water from a downspout
- a leak in an underground pipe
- automatic sprinkler systems
- compacted soil
Droughts and flooding caused by extremes in weather are out of our control, but there are strategies that can help your trees.
- Apply mulch around trees and shrubs.
- If a mature tree is drought-stressed, water deeply but infrequently. One inch of water applied every week at the drip line is best. Newly transplanted trees require more frequent watering until they are established.
- If the tree has too much water, correct the cause and cut back on watering.
- If the site problem cannot be corrected (such as a low-lying area that is always wet), choose a tree that can tolerate wet conditions. Similarly, choose drought-resistant trees for dry areas.
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