GardenLine | Common Saskatchewan Pests | Herbicide Use in Yards and Gardens

Holm is an Associate Professor with the Department of Crop Science and Plant Ecology. This column is provided as an extension service by the Division of Extension and Community Relations and the Department of Horticulture Science, University of Saskatchewan.

To most dedicated gardeners, weeds are an unsightly blemish which must be eliminated if the true, undiluted beauty of their ornamental plants is to be enjoyed to the fullest. What's more, there is a certain amount of satisfaction that comes with outwitting the pesky things. But that satisfied feeling can be most elusive, as weeds have proven to us countless times that they are formidable opponents.

To be sure, there are several things we can do to discourage weed growth in our yards and gardens. Preventive steps such as the use of clean topsoil, proper fertilization and watering of lawns, the removal of individual weedy plants before they set seed and careful disposal or composting of lawn clippings and garden refuse will all help to keep weed problems in check. But, in spite of all your best efforts, the day may come when you will want to enlist the aid of a herbicide to help battle the weeds.

Keep in mind, though, that declaring chemical war on weeds on a small city or town lot can entail considerable risk to both people and desirable plants. The careless use of a herbicide has caused more feuds between neighbours that you can shake a sprayer wand at. So, a few words of caution before you grab for that spray can.

First, is a herbicide really necessary? A few scattered weeds here and there may not look that great but perhaps a bit of hand weeding or hoeing may do the trick. The fresh air and exercise won't do any harm either. Save the sprayer for those tough problems.

If spraying seems the only solution, make sure you know the names of the weeds you are after before you go to the store. I still see a number of garden supply shelves stocked with "crab grass killer" and hear people talking about the terrible crab grass in their lawns. THERE IS NO CRAB GRASS IN SASKATCHEWAN! The crab grass killer that you see on the store shelf is completely useless for controlling the weedy grasses that infest lawns in Saskatchewan. As a matter of fact, there is no herbicide available that will selectively remove our weedy grasses from lawns.

Once you have the problem properly identified, purchase a product that is REGISTERED for control of that weed in yards and gardens. That means that you should use only those registered products which are classified and labelled as suitable for DOMESTIC use. Many of these home and garden domestic use products contain the same active ingredients that are found in agricultural herbicides. However, refrain from picking up a little sample of the agricultural version the next time you are out at your cousin Frank's farm.

There are a few good reasons for this. To begin with, the farm versions are usually much more concentrated than the city versions and so are more dangerous for the uninitiated to handle. Secondly, the labels on the farm versions of these products do not include mixing instructions for small areas. Do you have any idea what 1.1 L/ha of 2,4-D LV600 means in terms of treating your front lawn? Many herbicide damage problems are the result of over application, so it is important to use a product whose label contains proper mixing and application instructions for the job at hand. In fact, it is ILLEGAL to use a herbicide or any other pesticide in a manner not specified on the label. Thirdly, home and garden products can be disposed of in the household garbage. Left over agricultural spray material should NEVER be disposed of in this way.

Herbicides and all other classes of pesticides must be thoroughly tested for effectiveness and safety before they can be legally sold in Canada. This registration process is designed to ensure that the products which are sold will not cause unwanted side effects when they are used according to label directions. The ultimate responsibility for the safe use of pesticides lies with the user. Therefore, the first rule of pesticide application is to ALWAYS READ AND FOLLOW LABEL DIRECTIONS.

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Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.