One challenge that a city environment poses to trees is that it tends to amplify weather extremes. Without the protection of a forest environment, trees are more directly exposed to wind, cold and drought conditions. Trees in cities also don’t have the benefits that a forest floor does with regard to soil biology. City soils are often depleted and lacking in nutrients that trees need to thrive.

Keeping your trees well-fed will help keep them feeling and looking their best. There are a few routes to take when it comes to feeding your tree.

Deep Root Fertilizer

One way is with a deep root fertilizer. Our fertilizer is designed specifically for Toronto’s soil – which tends to be alkaline and clay-based. Along with the macronutrients that trees need for growth (Nitrogen, Phosphorus, Potassium), we include live biology and biostimulants and inject it right into the root zone of the tree. The fertilizer is low-salt so as to not dry out the root zone, and slow-release to minimize run-off.

Our goal is not only to provide essential nutrients to the tree, but to put microbiology back into the soil to create an atmosphere that allows for a sustainable, healthy soil system for your tree.

Biostimulant Soil Conditioner

If your soil needs an extra boost, you can inject a Biostimulant Soil Conditioner into the root zone of your tree, or do a soil drench in your planting and garden beds.

We have developed a custom biostimulant soil conditioner called ArborGain™. It combines humates, kelp, and other beneficial microbes into a (nearly) magic plant potion! This helps create a healthy home for your tree’s roots. It improves water and nutrient uptake, so it helps boost foliage, encourages root development and helps your tree become more drought resistant – this will be very helpful considering we’re expected to have a very hot, dry summer!


Mycorrhizae is our tiny secret weapon that you root system can use as an extra tool in its arsenal. Mycorrhizae is a unique type of fungus that does not produce its own food source, and relies on plants’ roots for energy. In exchange, it makes water and nutrients available to the plant that the plant would not be able to access on its own, thus creating a symbiotic relationship.

Having Mycorrhizae in the soil is beneficial to mature trees in a city environment where soil disturbance may have destroyed the delicate structure these organisms need to survive.

We often include a Mycorrhizae inoculation with our fertilizer and biostimulant injection treatments – we want to make sure we’re covering all the bases when it comes to keeping your trees well-fed!

Ask your arborist which way to feed your trees and plants is best for your landscape!


Be Good to Your Trees.

                         Because Your Trees are Good to You.


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