Landscape fabrics—what are they really?

Until recently, gardeners had two choices when it came to getting rid of weeds around their trees and shrubs, as well as the plants in their perennial gardens:
Wipe them out with chemical products, which are both dangerous and could kill the desirable plants, or get down on your hands and knees and pull them out by hand.
Not necessarily an easy job if you haven’t kept up with the weeds.
Landscape fabrics are an easy and more eco-friendly alternative than chemical herbicides for controlling weeds when used in combination with mulches.
Landscape fabrics can help eliminate weed growth around trees, shrubs, and plants for years when laid down before the application of an organic mulch, saving the time and energy you’d otherwise spend weeding and spraying herbicides.
Landscape fabrics are woven, non-woven, or spun-bonded synthetic petroleum products that, when laid on the ground around plantings, provide a physical barrier against weeds and tree roots.
Using a barrier for weed prevention is not new, of course, but in the past the only product available for weed prevention was plastic mulch.
As mentioned in a previous column, plastic mulch prevents plant roots from getting essential water, oxygen, and nutrients. It also can keep roots too wet, leading to an increase in root-rot diseases.
Unlike plastic, landscape fabrics breathe, letting air and water through, and don’t adversely affect the health of plants.
In fact, research has shown trees, shrubs, and plants with landscape fabrics around them grow just as well as ones without fabric, yet without the same weed competition.
The best place to use landscape fabrics is around trees and shrubs, or under stairs, decks, and patios where you don’t want weeds to grow. I don’t recommend using them for flower beds containing annuals, and they have very limited used in the perennial flowerbeds.
The reason for this is because when planting and transplanting annual flowers, gardeners tend to make many holes, which then allows weeds to grow out from underneath the fabric.
As well, many perennial plants expand slowly, allowing weeds to creep in around the base of the plant.
Remember that landscape fabric is a tool to reduce weeds, but it is not 100 percent guaranteed to prevent all weeds from growing. Even the best landscape products on the market have had tough perennial weeds (such as quack grass) eventually make their way through the fabric.
Then again, a few pieces of quack grass still are easier to pull out than a whole garden full of it, so it is still recommended you try a landscape fabric in your yard or garden.
There are many landscape fabric brands available to home owners. The best brands for suppressing weed growth are the ones with the smallest-sized pores (spaces between the fabric fibres).
Small pore spaces don’t allow weed or tree roots to penetrate and get a foothold in the fabric.
If the manufacturer hasn’t indicated the pore space on the packaging, you can raise the different brands up to the light and see how much light shines through.
The less light that penetrates, the smaller the pore spaces—and probably the less weed growth with that fabric.
Market research has found the “Weed-X” brand to have the smallest-sized pore spaces of all the fabrics tested. It also had the least amount of root penetration from weeds and nearby trees.
Another brand that performed well in research trials was “Dewitt’s Weed Barrier.” Hopefully, we are able to find one of these two brands for sale in the district.
Landscape fabric is an investment for your garden, so do not buy the “cheap” brand and expect great results. Most brands on the market now are UV-stabilized and can last for more than five years—even in direct sun.
Despite this, it still is highly recommended that you cover the fabric with a mulch product of your choosing.
The latest research in landscape fabrics is creating a new generation of treated fabrics that are even more effective in controlling weeds regardless of the types and depth of the mulch.
An exciting product expected to reach the marketplace in the next few years is a non-woven landscape fabric impregnated with copper. Whenever tree or weed roots come in contact with the copper, they’re essentially stunted, thus making the fabrics last even longer.
The investment you put into a quality landscape fabric will reward you in the end with less labour for weeding over a longer time span. Better quality means a longer time before it has to be replaced.
When installing landscape fabrics, first clear the area of all existing weeds. When installing in a newly-developed garden, I suggest laying down the fabric across the expanse of the garden, with at least a six-inch overlap between pieces, and anchor the fabric with metal pins you can make from pieces of coat hanger or other strong wire cut and bent into a U-shape.
Then position your plants in their pots on top of the fabric until you are satisfied with the layout.
Once ready to plant, cut an “X” shape in the fabric equal in length to the diameter of the pot for each plant (do not cut away the flaps that the “X” cut makes; rather, push back the flaps and then dig a hole to accommodate the plant).
Once correctly planted, re-arrange the flaps back down on the soil, adjusting by folding around the plant. Only cut away excess if you really have to. Pin the flaps down once positioned.
It is best to cut the holes and plant the plants one at a time in order to allow for adjustment of the fabric as you go. Once all plants are planted and the fabric is secure, you now are ready to cover with a mulch product.
If you are putting the fabric down in a garden with established plants, you will have to do a lot of cutting and overlapping around the established plants.
Make sure that when installing the fabric that you bring it up around the base of the plant as best as you possibly can in order to reduce soil exposure allowing for weed growth.
This can be quite labour-intensive and frustrating, so you may want to use newspapers instead.
As mentioned before, landscape fabric is more ideal for using around trees or shrubs, or a garden considered finished in terms of planting and re-arranging plants.
For a perennial beds, I highly recommend using thick layers of newspaper (one section of the Wednesday Times folded in half) as a “landscape fabric.” The newspaper is a natural product and is organic, so it will biodegrade over time.
It usually last two-three years before it is absorbed into the soil, thus making it a good layer between the soil and your mulch product.
In perennial beds with multiple plants, the newspaper is easy to manipulate around the bases of plants. You can tear, fold, and cut newspapers as needed (just ensure you maintain a consistent thickness of the paper across the whole garden).
To keep the papers in place while you work, water them to weight them down.
Do not work too far ahead of yourself before applying the layer of mulch. You can position it in patches to hold down the papers first and then fill in between the patches later.
Whether you use newspapers or invest in landscape fabric, I think you will be surprised at how well it can keep the weeds at bay. The initial investment of time and labour can reward you with extra time to sit and enjoy your garden—weed free.

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