I’m planning to put wood mulch or wood chips in my shrub beds. How can I do this to make sure that weeds don’t come through?

Wood chips, wood mulch, and decorative stone are a great way to enhance your landscape, particularly where it’s difficult or impossible to grow grass. I can’t tell you how often we see decorative rock or wood mulch that is not properly installed. In order to keep weeds and grass from growing through wood mulch alone, the mulch needs to be at least 10cm thick if it is a heavy mulch, and 16cm thick for lighter mulches. Keep in mind that both light and heavy mulches will settle by as much as 20%. New mulch should be added after one year to insure the proper depth is maintained. If you prefer not to use such a large volume of wood mulch, a weed barrier may be used. Heavy duty weed barrier is available at most garden centres. It comes in rolls either four feet or five feet wide. Simply measure the area you need to cover, purchase the weed barrier and cut to fit. Weed barrier has a shiny smooth side and a softer cotton-like side. Make sure to install the weed barrier with the shiny side up. In the case of decorative rock, there’s no choice but to use a weed barrier. The price of decorative rock and the volume required to prevent weeds from sprouting make it cost prohibitive. Keep your surroundings in mind as well as the seasons. I often see homeowners who live in heavily treed areas lay down tones of wood mulch, only to have to add more and more each year because their lawn care service has no choice but to remove it along with the leaves in the spring and fall. In heavily treed areas as well as under pine trees, large stone, ¾” or larger would be best since it would stay in place while you or your lawn service rake or blow the leaves off of it. Under pine trees, larger stone will conceal the vast amounts of pine needles that are shed annually by the tree. Do this right the first time. If you hire a landscaper, make sure they use a heavy weed barrier. If you’re installing mulch, make sure it’s thicker than you need and expect to top it up a little now and then. Taking shortcuts now will lead to endless weed picking that will tarnish the clean look that you’re trying to achieve in the first place, and will cost you hours on end in weed picking for as long as you have that bed.