Trees and yards

Report damage and request trimming for city-owned trees, learn more about ash tree replacement, tree care tips, and yard maintenance standards.

Trees on public property (including parks, green spaces, trails and alongside roadways) are the city's responsibility to protect and maintain. We have a public tree bylaw that protects them from being cut down or harmed.

We're working to update our urban forestry guidelines and will publish them here when available.

 On this page

  1. Gypsy moth control
  2. Public tree services
  3. Ash tree replacement
  4. Taking care of public trees
  5. Yard maintenance standards

Gypsy moth control

Local gypsy moth populations are higher than usual in 2021.

The city is removes gypsy moth caterpillars from city-owned trees. We encourage residents to remove them from trees on private property.

The best way to contain them is to:

  1. Wrap burlap around the trunk of the tree, a couple of feet above the ground.
  2. Collect the caterpillars as they come down the tree canopy during the day and get caught in the burlap.
  3. Check bands regularly and scrape caterpillars into a container with soapy water. Leave them for a few days and dispose in garbage.

We do not recommend using commercial sticky traps as they can kill insects, pollinators and birds.

The caterpillars have several native predators. These include mice, birds, chipmunks, skunks, raccoon, wasps and flies.

Background info

Gypsy moth populations peak every 7 to 10 years. When moths are in the caterpillar stage they can be found in crevices in the bark of trees.

Thankfully infestations are not a yearly occurrence and healthy trees are able to recover even after significant defoliation.

Public tree services

These services only apply to trees on public property such as parks, green spaces, trails and alongside roadways.

Report damage

If a tree has been damaged by storm and poses an obstacle or risk to public safety, call us:

If you believe someone is harming a city tree, report it to municipal enforcement.

Request maintenace

Request maintenance such as trimming, pruning, or disease/pest diagnosis at 519-886-2310 (Monday to Friday, 8:30 a.m. to 4:30 p.m.).

Pruning is done by certified arborists who work to these standards:

  • the lowest branch over public sidewalks no less than 3 metres (8 feet)
  • the lowest branch over a roadway no less than 4 metres (14 feet)
  • trails and walkways must have 3 metres (10 feet) of vertical clearance and 30 centimetres (1 foot) beyond each edge of the trail

Request new tree

Call 519-886-2310 to request a new tree on public property.

Ash tree replacement

Emerald ash borer is a non-native insect that feeds under the bark of ash trees, disrupting the circulation of water and nutrients. Infested trees usually take up to five years to die.

We're committed to maintaining ash trees where possible and following a sustainable plan for tree management and removal.

Inspection, marking and removal

We inspect ash trees on city property on an annual basis, maintaining them whenever possible and replanting as quickly as possible after removals. Based on tree health, form and location, injections with TreeAzin insecticide are sometimes used to prolong the life of ash trees.

Residents will be notified of tree removals and replantings close to their property. Trees to be removed are marked with two red dots.

If a city ash tree appears unhealthy and isn't marked, call us at 519-886-2310 and we will inspect it.

Ash trees on private property

If you have ash trees on your property, there are some options to prolong their life span:

  • monitor them closely for signs of decline, such as loss of leaves/dead branches in upper areas, thin crowns, bark splitting or exit holes
  • do not plant new ash trees, and remember that infected trees die quickly and become hazardous
  • insecticide injection may prolong the life of your tree long enough to wait for new treatment options
  • chemical treatment is most effective between June and August
  • tree removal is expensive, but may be necessary based on health of the ash tree. It is important to weigh your options and seek advice on the effectiveness of chemical treatments versus removal. 

Pest removal

We do not spray for insects because of the provincial pesticide ban. Visit the Ministry of Agriculture, Food and Rural Affairs website for more information

We do not remove insect nests within three metres (10 feet) of the ground unless they pose a safety issue. Bees, wasps and hornets generally do not cause a threat to human safety and play important roles in our environment as pollinators, predators, scavengers and prey.

Taking care of public trees


Young trees need lots of water to grow. We provide a water bag for spring-planted first year trees. This bag can be topped up at any time.

For subsequent years, a long slow soak is best so the water has time to move deep down into the soil and encourage deep rooting. Leave a hose to trickle slowly for at least 45 minutes or use about 20 gallons of water, poured slowly. Water about 2-3 feet from the base of the trunk a couple times a month or as needed during drought.

When watering trees or lawns, follow the Region of Waterloo's watering schedule. Water from rain barrels or watering cans any day.

To help keep soils moist we use organic mulch. Keep mulch and other materials away from the trunk to avoid disease, shallow rooting, and rodent damage.


During the first year, a tree is spending a lot of energy growing roots. It is suggested to avoid fertilizer during the first year, especially those high in nitrogen. In future years a slow release organic fertilizer such as bone meal is recommended.

Requirements for digging around trees

Diagram of the protected root zoneIf you need to dig around a city tree's protected root zone (see diagram), follow these requirements:

  • all excavations using hand tools, air spades or trenchless techniques need to be carried out with great care to avoid damage to as many roots as possible
  • all roots over 25mm in diamter should be worked around and retained
  • any root cutting should be done with a sharp handsaw or secateurs (clean, straight cuts); size of the wound should be kept to a minimum 
  • mats of smaller roots (<25mm, including fibrous roots) should be retained
  • smaller roots can dry out and die when exposed, particularly in warm or windy conditions - they should be covered and protected with damp material until excavation is back filled
  • cutting of roots with a diameter > 25mm must be preapproved by the Manager of Forestry
  • when backfilling, do not tamp the soil too tightly, in order to allow oxygen and water to fill loose soil spaces
  • no more than 25 percent of the roots within the dripline for any tree should be cut or damaged
  • take extra precaution around sensitive and intermediate trees 

Use the following table to determine how sensitive a tree might be to root disturbance:

Species Tree Severance
American Elm Tolerant
Basswood Intermediate
Black walnut Sensitive
Bur Oak Tolerant
Butternut Sensitive
Green ash Tolerant
Hackberry Tolerant
Honeylocust Tolerant
Ironwood Sensitive
Mountain ash Tolerant
Red maple Tolerant
Red oak Tolerant
Silver maple Intermediate
Sugar maple Intermediate
White ash Tolerant
White oak


If you have questions about how to proceed around a city tree, call us at 519-886-2310 for advice.

Yard maintenance standards

Contact bylaw at 519-747-8785 or to report yard maintenance issues.

Lawn watering regulations and restrictions

Lawn watering is regulated by the Region of Waterloo's Water Conservation Bylaw. Visit their website to learn more about watering days, and to apply for exemptions.

Front yards

According to ourlot maintenance bylaw, you must keep your front lawn free of "undesirable material" including:

  • refuse, rubbish, garbage, brush, waste, litter and debris
  • injurious insects, termites, rodents and other pests
  • growth of grass or weeds in excess of six inches
  • noxious weeds (see below)
  • branches or bushes which overhang the sidewalk or road
  • dead, decayed or damaged trees
  • unused or unlicensed motor vehicles or trailers
  • stagnant water
  • machinery or parts thereof
  • all furniture designed for indoor use

Noxious weeds

To comply with ourlot maintenance bylaw, you must keep your yard free of three types of noxious weeds:

  • giant hogweed
  • poison ivy
  • ragweed

Be careful when removing these weeds. Visit the Ministry of Agriculture, Food and Rural Affairs website for tips on identifying and getting rid of giant hogweed, poison ivy and ragweed.

Invasive plants

Residents planting invasive species in private gardens are an increasing concern, especially where they grow close to public green spaces. The Grow Me Instead guide provides tips on growing species that are best suited to growing in our environment.

View some of the common invasive plant species found within the Grand River watershed. You can report sightings and observations of invasive species through EDDMapS Ontario.


Encroachment is the unauthorized use of public land for personal purposes, such as placing a shed, fence or other structure beyond your property line. This includes birdfeeders, play equipment, wood piles, pools, trailers, composters and gardens.

Our encroachment policy also regulates altering public land: you may not mow, prune or remove vegetation, plant trees or shrubs, or dump waste on public land.

Penalties for encroachment are up to $10,000. Our encroachment policy (PDF) sets out the process to remove encroachments and restore land at the expense of the person who encroached on it.


In Ontario you need a license to use pesticides on your lawn. Visit the Ministry of Environment's website for more information.