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Tree Care

Proper tree care is critical for the establishment of newly planted trees and beneficial to the health of established trees, especially during drought conditions.


Water is the most critical factor for tree establishment, health and growth.  Please do not allow newly planted trees to go without water!

A new tree needs to be watered with a maximum of 10 litres (2.5gal) twice a week (or every 3 to 4 days) for the first month and then once every 7 to 10 days for the next 3 years.  Watering frequency should be increased during hot dry weather. 

Water established trees during dry periods using 45 litres (10 gallons) of water for every 2.5 cm (1 inch) of tree diameter.  The soil should be saturated to a depth of 8 to 10 cm (3 to 4 inches).  

How to water a newly planted tree:

  • A drip irrigation system works well around the base of the tree, or place a garden hose over the root zone.
  • Turn your tap on low and let the water trickle out.
  • Sufficient water has been applied when the soil is saturated. 
  • Keep in mind that tree roots also need oxygen.  Allow the surface soil to become dry before the next watering.
  • After a few months, expand the watering beyond the root zone to the drip line.  This will encourage the roots to fan-out into the surrounding soil.
  • Do no rely on lawn irrigation (e.g. sprinklers) when it comes to watering your tree.

Mulching & Maintaining the Tree Well

Mulching conserves soil moisture, keeps soil cool, controls weeds and other competing vegetation.  The City applies approximately 5-8cm (2-3in) of mulch over the tree’s root zone at the time of planting.

Mulching and tree well tips:

  • Mulch helps to control weeds and grass which can compete with tree roots for water and nutrients.
  • Keep mulch away from the trunk to avoid bark injury caused by fungi, pests and rodents.
  • Keep the tree well free of weeds and grass to protect the tree from damage caused by lawn mowers and weed trimmers.
  • Trees planted in low areas, compact soil or clay soil will need adequate oxygen and may require less mulch.
  • Keep landscape rocks, fabric and artificial turf away from the tree.  These products are not recommended because they change the soil composition to the detriment of the tree. 

Fertilizers & Herbicides

The City does not fertilize trees. Fertilizers can cause trees to produce soft, lush, weak growth that may not harden-off in time for winter. Some fertilizers that are meant for annuals and turf grass are harmful to trees. If applying fertilizer to your lawn or garden, keep it far away from the tree.

Herbicides are also detrimental to trees. Signs and symptoms of herbicide damage appear soon after contact and are easy to identify. Keep herbicides away from the tree’s root system, branches, trunk and leaves. Even a small amount of herbicide spray, drift or contaminated water can harm or kill a tree.

Tree Maintenance 

Maintenance of City-owned trees located on boulevards, centre medians and in parks is the responsibility of the Urban Forestry Section.  For more information, visit Tree Maintenance & Inspections.