Weed Vs Grass: How To Tell Them Apart?

As a gardener in Canada, identifying what a weed and grass in your lawn are can sometimes become tricky, especially if you don’t have much experience in gardening. A weed is a plant that grows in an unwanted area such as in your lawn, garden, or on the roadside. Common weeds in Canada include; Crabgrass, Dandelions, Canada thistle, Clover, and Ragweed.

The grass is the desirable variety of plants that you grow in your lawn. Weeds inhibit the proper growth of desirable grass in your turf and disrupt lawn uniformity. They compete with desirable grass species for water, light, space, and nutrients.

But how do you tell the difference between grass and weeds? Weeds are generally grouped into three categories as; grass and grass-like weeds, broad-leaf and woody plant weeds.

For an effective weed management program, you must properly identify different types of weeds and understand their life cycle. This will help you know the best strategies that you can apply to control them and the right herbicide to use on a particular weed.

Understanding the weed life cycle

Lawn weed grass can be grouped into three life cycles, namely; annual, biennial, and perennial. Annual weeds are plants that complete their life cycle in one growing season. Biennial requires two growing seasons while perennial weeds need more than two growing seasons to complete their cycle.

For instance, seeds of annual weeds will germinate in spring. They will start developing vegetative growth at the end of spring or summer then produce seed and die during the fall season. Crabgrass, bluegrass, common chickweed, and prostrate knot weed are common annual weeds.

Weed Identification process

To positively identify weeds, it’s essential to, first of all, understand the difference between broad-leaf weeds and grass weeds.

Broad leaf Weeds.


Broad-leaf weeds as the name suggests, they have wider leaf blades compared to grass weeds.

There are unique leaf features and characteristics that can be used to identify broad-leaf weeds. They have a broader leaf shape and the main vein which divides the leaf into two and other smaller veins on each half, forming a net-like pattern.

The arrangement of leaves on the stem is another simple way of distinguishing broad-leaf weeds. They either have alternately arranged leaves (whereby a leaf grows on the node of one side of the stem, and the other thrives on the opposite upper side of the stem) or leaves growing in different directions.

Other species of broad-leaf weeds have leaves which develop in a circular pattern all starting from a central growing point. Different varieties grow and spread through underground stems (rhizomes) or by creeping upwards at above ground stems (Stolons).

Broad-leaf weeds have a fibrous root system, and some also have a firm tap root. Another identification feature of broad-leaf weeds is the colorful flowers that these common weeds produce at a particular season.

Grass weeds

Their leaves structure and shapes can easily identify grass weeds. They have long but narrow leaves with veins which run parallel to each other.

Grass weeds have similar leaf shapes among certain species, and unlike the broad-leaf weeds, they don’t produce colorful flowers which are conspicuous in a given time of the year.

The easiest method of identifying grass weeds is to focus on their growing habits, unique vegetative structures, and their seed heads features.

There are three different growth habits of grasses, namely; bunch-type, stoloniferous, and rhizomatous.

In bunch-type weed grass growth habit, a new stem grows from a bud in the crown and grows vertically but remains bounded by the leaf cover. This method is commonly referred to as tillering.

Grass weeds with rhizomatous growth habits, lateral growth is achieved by horizontal creeping on underground stems known as rhizomes which produce nodes resulting in new tillers.

In stoloniferous weed growth habit, the lateral growth is achieved by horizontal creeping above-ground stems known as Stolons. They produce nodes which eventually give rise to new tillers.

When identifying grass weeds based on their unique vegetative characteristics, we focus more on the leaf blades and also the collar structure. Leaf-blades of different varieties of weed grass differs in terms of width and hairiness. The collar is the area between the leaf blade and leaf sheath. Depending on the type of grass weeds, this region may contain both ligules and auricles or not.

Different types of grass weeds also have different shapes of seed heads. The most common distinguishing seed head shapes are; compact spikes, divided spikes, and open-panicle seed heads.

Follow the above-listed weed identification features to distinguish different grass and grass-like weeds in your lawn easily. Common weeds grow in your yard and tthrive more than your desired plant variety because of an existing gap in proper lawn maintenance practice.

To effectively control these typical lawn and garden weed grass, ensure you have made the right seed selection of your turf-grass. Besides, applying lime and fertilizer, adjusting soil PH levels, watering, mowing, pest and disease control measures can go a long way in helping you achieve a vibrant, healthy and weed-free lawn and garden.