'Tis the Season for Summer Drought
After a very dry spring and summer you may be noticing symptoms of drought in your trees:
- Yellowing and/or wilted leaves (like the River Birch, Betula nigra, pictured below)
- Smaller leaf size towards the ends of branches
- Leaves turning colour and falling too early
- Dead spots on leaves
Why do trees experience drought stress?
Water helps trees maintain their structure. Trees are like giant straws - water evaporates from the leaves, pulling columns of water up through the living wood from the roots. If there is not enough water in the soil, the cells that carry the water will collapse and water will no longer reach the top of the tree and tips of the furthest branches. This is why the leaves at these locations wilt and die.
Dissolved nutrients are also transported in water from the roots to other areas of the tree, so if water cannot get to the places where it is needed, neither will nutrients, slowing down growth and potentially causing parts of the tree to die back.
Three things that you can do to prevent drought stress:
1. Water your trees slowly and deeply, preferably with a soaker hose or Treegator™ bag, to make sure that water percolates down through the root zone, about 12-18 inches (30-45cm) below the surface of the soil. If you choose to water with a non-soaker hose or sprinkler, water in the evening!
2. Mulch your tree in the spring, making sure that the mulch is only 3-4 inches (8-10cm) deep, and that it is kept away from the trunk (think “donut”, not volcano”). The point of mulching is to prevent water from evaporating from the soil into the air, but the reverse is also true, so don’t mulch during a drought!
3. When planting, choose trees that are appropriate to your site’s moisture conditions. Look for ideas in this City of Toronto info sheet!
What can I do if my trees are already suffering from drought?
Prune: It is very important to have dead branches pruned out of the tree if they are a hazard to people, animals or objects that may be underneath. It is recommended to leave as much of the live branches on as possible, though, at least until the tree is less stressed.
Water: It is never too late to begin watering properly. It may not save the damaged branches and foliage but it will help the tree recover and produce healthy new growth.
Services that we offer
Here are some services that may help you with your drought-stressed trees this season:
- Tree and shrub fertilization
- Shrub pruning
- Tree removal
Call for a free assessment and estimate: (905) 872-9103
Written By: Anna Mernieks July 22, 2016;