We’re fully into summer now and you might have noticed that your trees are feeling the heat!

City soils make access to water hard enough on our trees without the added stress of extreme heat. Compacted soils and an abundance of hard-scape means that, more often than not, more water is running off or evaporating than is getting deep into the soil where the roots need it most.

Without enough water, the entire tree suffers.

Here are some of the negative effects caused by drought:

  • Leaf wilting and crown die-back.
  • Small, stunted foliage. 
  • Decreased resistance to pests and disease. 
  • Structural weakening and a greater vulnerability to branch drop. 
  • Weakened root structures. 
  • Total collapse of newly installed plants. 

What can be done to get our trees and shrubs through this difficult time?

1. Water your tree.

On younger trees deep watering should be conducted two to three times per week during drought conditions. We suggest a hose on a slow dribble for 30 to 40 minutes.

  • Move the end of the hose three times during this process to soak all sides of the root zone, about 12”-18” from the tree trunk.
  • A soaker hose run for the same amount of time solves the issue of having to move the hose end around. Avoid spraying the foliage with water during the day as this can contribute to the leaves drying out and looking shrivelled.

2. Renovate your soil.

  • Your arborist can use a high-pressure air tool to aerate the soil around your trees and help ease compaction.
  • Have aeration and watering tubes installed around the trees’ root zones – this allows for water to reach the roots at depth and prevents re-compaction

3. Add beneficial ArborGain, mycorrhizae and Biochar to the soil.

  • No soil renovation is complete without adding essential nutrients and microbiology to your soil.
  • ArborGain contains many ingredients that improve the overall health and structure of your soil, and has the added bonus of containing Yucca – a desert plant that helps your tree with water retention and drought tolerance. 
  • Mycorrhizae is a fungus that forms a symbiotic relationship with your trees roots – it increase the surface area of the tree’s root system and allows for improved nutrient and water uptake.
  • BioChar is the new soil superhero on the block! BioChair acts like a sponge and will hold water in and around the root system for your tree to access. It also prevents the soil from re-compacting, so it also improves drainage and allows for oxygen and water to better reach your roots.

Doing nothing for our trees and shrubs during this period of dry weather will result in plant stress, plant damage and even plant loss. This can be catastrophic for our individual landscapes, the entire community and the urban forest as a whole. Cities have never been an easy place for trees. Now is the time for us to provide additional support for our green spaces in order to survive the upcoming months and ensure a healthy and vigorous future for our woody plants. Consult with your Arborist today.

Be good to your trees.


Kristie Nairn, MA, MMst
Cohen & Master Tree and Shrub Services Ltd.