Lawn Care

Weed Control Program


One of the primary ways that a weed-free lawn can be maintained easily, cheaply and with a minimum of effort is through good lawn care practices which encourage the natural vigorous growth of turfgrass. Most weeds cannot compete with dense, healthy turf. The most important practices for weed control are detailed below.


Regular mowing induces the sod to become thick and dense. Grass should be cut at a height of 2.5″ to 3″; any shorter may cause an invasion of weeds. In addition many weeds cannot survive having their tops repeatedly cut off.


Aerating removes plugs of dirt from the lawn so that air, water and nutrients can reach the roots. Over time, soil can become hard and compacted; therefore, by aerating regularly (spring and fall) you will loosen up the soil and feed the roots. Aerators can be rented from a rental company or you can hire a landscape company to do this for you.


According to the Ontario Ministry of the Environment, late summer or early fall is the best time to apply fertilizer. They can also be applied in the early spring.

In order to minimize any adverse affects on the lakes, use “organic” fertilizers (meaning most of the nitrogen is water insoluble).

The following brands of fertilizers may be used if necessary. Follow the manufacturer’s instructions with respect to quantities:

  • CANAGRO VIGORO Natural Fertilizing 5-4-7
  • NUTRITE Vitorganic 8-2-0
  • CIL Mother Earth 100% organic Summer Lawn Food 8-2-0
  • SO-GREEN Envirosoft 6-2-0
  • MILGANIT Green & Fairway Fertilizer 6-2-0

Tip: Leave your lawn clippings on the lawn after you mow — they make an ideal (and free) fertilizer. As they break down they release nitrogen into the soil. Use compost or all-organic fertilizer in the fall to feed the roots of your lawn.


Excessive thatch can lead to poor grass growth and weed encroachment. Dethatch in the spring.


During a period of drought, to prevent weeds from becoming established it is important to give one weekly soaking. Frequent light waterings encourage germination of shallow rooted weeds such as crab grass and creeping bent grass.


Reseed sparse areas before weeds become established.


If there are only a few weeds, pulling them by hand or with hand tools may be preferable to other methods of weed control. This not only gets rid of the immediate problem but also prevents those plants from producing seeds resulting in more weeds later in the season or in the following years.


On April 22, 2009, Ontario’s ban on cosmetic pesticides came into effect. The use of pesticides to control pesky weeds and insects for purely cosmetic reasons is an unnecessary risk to our families and pets, especially when you can have a healthier lawn and garden without chemicals.

The Ontario government listened to medical experts – like the Canadian Cancer Society – who have made a convincing case for reducing our exposure to pesticides, particularly children who are generally more susceptible to the potential toxic effects of pesticides.

While it means that many herbicides, fungicides and insecticides can no longer be sold or used for cosmetic purposes on lawns and gardens, you can still have a beautiful lawn and garden using natural methods and greener alternatives.

Gardeners can still purchase and use certain lower risk pesticides and biopesticides to manage weeds, insects and plant diseases. The biopesticides are those designated by Health Canada’s Pest Management Regulatory Agency. Lower risk pesticides have characteristics such as low toxicity to humans, minimal impact to the environment, and act in a non-toxic way in controlling intended pests. You can view a list of these products in their entirety on the ministry’s website at To search for a specific product, use the new database on the ministry website:

Under provincial pesticide legislation, a pesticide must be registered under the Pest Control Products Act administered by Health Canada’s Pest Management Regulatory Agency and classified for legal sale and use in Ontario. These pesticides must only be used according to label directions.

Tip: Corn Gluten Meal is also a great way to keep lawn weeds at bay. Available at most garden centres, it works to inhibit growth during seed germination. Apply in the early spring and wait at least 4 weeks before over-seeding.


There are no herbicides available for weed control in established gardens and flower beds without the risk of damaging or killing desirable flowers and shrubs. Usually one must resort to pulling by hand, hoeing, competition and/or mulching.


A single hoeing will kill most annual weeds by cutting off all weeds to just below the ground surface. Perennial weeds are more persistent but repeated hoeing throughout one growing season will kill most and repeated hoeing into the second season will kill the rest.


Planting flowers and shrubs closer together than usually recommended may interfere with their shape and productivity, however, by shading the soil it can reduce the number of late germinating weeds.


Mulch, particularly when used with landscape fabric, is effective in preventing weed growth. It also conserves moisture and moderates soil temperatures. Mulches can be organic (such as bark or wood chips) or inorganic (such as stones, pea gravel or brick rubble).


The following expands upon information previously distributed concerning “fertilizer free gardens” and provides an extended plant list.

On all lots, but particularly waterfront lots, it is encouraged that “fertilizer free gardens” be planted. Unlike lawns and most other garden plants, the plants listed below require little topsoil and no fertilizers to grow. Keep in mind that on waterfront lots, mature height of plants within 75 ft. of the water must be less than 3 ft.

Most of the following “fertilizer free” plants listed below are native plants and all are very hardy in the Ottawa area. They are commonly found in local nurseries:


  • White Spruce (Picea Glauca)
  • Norway Spruce (Picea Albies)
  • Austrian or Black Pine (Pinus Nigra)
  • White Pine (Pinus Strobus)
  • Canadian r Eastern Hemlock (Tsuga Canadensis)
  • Eastern White Cedar (Thuja Occidentalis)


  • Amur Maple (Acer Ginnala)
  • Serviceberry or Shadblow (Amelanchier Canadensis)
  • Red Osier Dogwood (Cornus Stolonifera)
  • Russian Olive ( Elaeagnus Angustifolia)
  • Choke Cherry (Prunus Virginiana)
  • Mountain Ash (Sorbus Americana)
  • Common Lilac (Syringa Vulgaris)
  • Nannyberry or Wayfaring Tree (Viburnum Lentago)
  • High Bush – Cranberry (Viburnum Tribobum)


  • Meadow Sweet (Filipendula)
  • Potentilla or Cinquefoil (Potentilla Friuticosa)
  • Rugosa Rose (Rose Rugosa)
  • Raspberry (Rubus)
  • Arctic Willow (Salix Purpurea Gracilis)
  • Snowberry (Symphorecarpos Albus)


The following plants are good for shady locations:

  • Japanese Spurge (Pachysandra Terminalis)
  • Periwinkle (Vinca Minor)

It is highly recommended that for waterfront lots, instead of a lawn, a “fertilizer free garden” of the following ground cover plants, which thrive in full sun, be grown within 20 ft. of the lake along at least 75% of the length of the shoreline. They will absorb nutrients before they enter the lake, thus minimizing aquatic plant and algae growth. In addition they will minimize soil erosion into the lake. They can also be used for other areas of your garden.

  • Adjudge or Boggled (Adjudge Reptans)
  • Bearberry (Arctostaphylos Uvaursi)
  • Trumpet Vine (Campis Radicans)
  • American Bittersweet (Celastrus Scandus)
  • Virginia Creeper (Parthenocissus Quinquifolia)

Landscaping Companies that are 100% pesticide-free:


The City of Ottawa has striven for accuracy in these listings but recognizes that they may not be complete. To update the listings or to be added to either of the lists, please call 613-724-4227.

The material provided is for information only and should not be construed as professional advice. The listing or omission of companies does not constitute an endorsement or disapproval by the City of Ottawa.

  • Appleseed Organic Lawn Care 613-224-7336
  • Artistic Citywide Rototilling & Aeration 613-769-7079
  • Avant Gardeners 613-839-0280
  • B&C Landscaping 613-523-1952
  • Forevergreen Canada Inc. 613-730-9595
  • Hansen Lawn & Garden Ltd. 613-260-8175
  • Natural Choice 1-866-GRUB-GUYS (613-823-9257)
  • Nature’s Way Design Company – Consultant Services 613-831-1852
  • Precision Landscape Group Inc. 613-721-6337
  • The Pond Clinic (Turf Grass Alternatives) 613-225-POND (613-225-7663)
  • Turf’s Up Landscaping & Property Maintenance Inc. 613-596-3127