There are many ways to control or reduce weeds in a lawn. One option is to apply a preventative pre-emergent control; however, there is currently no single product that covers the entire spectrum of broadleaf weeds. Most commonly used are post-emergent herbicides when controlling weeds in a lawn or landscape.
The natural way to get rid of weeds in your lawn is to hand pick them out. On smaller size lawns and mulch beds this is an effective way to control a small number of weeds. If you can pick the annual weeds before they flower and produce seed, you can aid in reducing the number of weeds that regrow. Keep in mind, weeds have roots that grow underground, hand pulling tears off the top foliage but the plant’s roots are left behind which can then regrow the plant. You need to remove all the roots to be successful and this is a difficult way to achieve it.
Types of weeds
Cultural practices also play a key role in creating a more weed free lawn. Following these simple steps helps your lawn to be the healthiest it can be.
Selective herbicides are another way to get rid of weeds in a lawn. The most widely used selective herbicides work by disrupting chemical processes happening inside the weeds. The herbicide mimics a natural plant chemical that stimulates uncontrollable growth. The weeds’ growth happens quicker than the plant can handle and dies.
How to kill weeds in the lawn
There are three different types of weeds in every lawn and landscape bed. All can be controlled; however, some are easier than others.
In spring, it can be difficult to determine what is a weed and what is a flower, especially when things are just emerging. Do weeds have certain tell-tale characteristics that make them easier to identify?
JP: Since every province is unique, it's wise to refer to websites with information specific to the province you live in.
What should you do if you aren't sure if it's a weed or a flower?
JP: No, all weeds come from the kingdom of plants and all weeds will produce flowers (or equivalent reproductive organs). They're definitely the underappreciated relatives of some of our most beloved garden plants. For example, what may be considered a weed in British Columbia might be considered a garden gem in Ontario. On a larger scale, a beautiful culinary herb that is desirable in Europe and brought to North America for its desirable characteristics can become a menace — even invasive. Such was the case with Garlic Mustard (Alliaria petiolata) which is now a common unwelcome resident in many Ontario gardens.
Common Milkweed (Asclepias syriaca) is an example of a North American native plant that gained a negative 'weedy' reputation. However, with the renewed interest in the health of pollinators (bees and butterflies) and the challenges they face, this species is finally turning around. Milkweed is now recognized as a desirable species to cultivate in the garden because the benefits it provides to the ecosystem far outweigh its aggressive tendencies. This beautiful perennial plant which features large rounded leaves, spherical clusters of pink flowers, and unique seed 'pods' will spread and colonize an area via its horizontally spreading underground roots. All parts of the plant contain a thick, white, milky sap which can be toxic to animals but provides benefits to the insects which feed on it — the monarch butterfly perhaps being the most famous. The monarch lays its eggs exclusively on Milkweed leaves and when the larvae hatch, they feed on the leaves until they're ready to become a chrysalis and, ultimately, a butterfly. Adult monarchs get energy-rich nectar from the flowers of the plant.
A plant expert answers questions about every gardener’s nemesis
Do weeds harm the garden?
JP: First, remember that all weeds are plants too. Best advice is to be patient, sometimes the identity of the plant can't be guaranteed until the plant is flowering so waiting is often the best thing to do. Proper identification is the most important step in determining what you'll need to do to either abolish or control a plant. And some plants can be toxic to humans, so it's important to know what things are before dealing with them. Wear proper protective gear if you are uncertain.