Reduction or elimination?
According to Andy Blanchford, owner of Blanchford Landscape Contractors, Inc., Bozeman, Montana, contractors need to educate their clients about maintenance rather than “telling them weed barriers will solve the problem. Weeds are a fact of life and they are geographically specific. It is important to know the characteristics of the weeds and invasive species in your area, and know what tools you need to kill them.”
“Weed barriers protect your plant investment, which is generally your biggest cost. Fabric is one step in an o v e r a l l weed reduction strategy,” says Steve Gambla, owner of Ground C o v e r Industries, C h i c a g o , I l l i n o i s . “ P e o p l e s h o u l d n ’ t c o n f u s e Photo courtesy: DeWitt weed barriers with a lack of maintenance. Just like you have to change the oil in your car, you have to do some maintenance in your beds. Fabric will help reduce and even eliminate some of your weeds, but it can’t get them all . . . because nature doesn’t work that way.”
Monson adds, “We have obnoxious weeds here in Michigan, including Canadian thistle. Many of my clients are older, and or elderly, they just can’t do the weeding the way they used to, so I explain to them that there’s no such thing as a maintenance-free landscape, but weed barriers keep future weeding to a minimum. It reduces, it doesn’t eliminate,” says Monson.
Landscape fabric benefits the landscape in a number of other ways. First, it allows air and water to flow directly to the plant. Weed barriers also provide a barrier against evaporation, thereby decreasing nutrient leaching, and reducing the duration and frequency of waterings.
The barriers don’t wick water from the soil, so the fabric creates a musty habitat perfect for soil fermentation, which helps beneficial microbes and microhizal fungi grow. Microhizal fungi benefit the landscape by developing symbiotic relationships with plants, providing mineral nutrients the plants cannot produce themselves in exchange for carbohydrates the fungi need.
“Customers want relief from weeds, so that’s why we developed our Weed-Barrier Pro, a product made of spunbond polypropylene, that is guaranteed to provide 100% weed control without chemicals,” says Larry DeWitt, founder and CEO of the DeWitt Company.
He not only stands behind his product, he put it to the test in his yard against nutsedge. “Nutsedge develops a needle-like tap root and you can imagine how most fabrics, even our earlier products, wouldn’t provide much resistance to that needle. Nutsedge thrives under most weed barriers, but not Weed- Barrier Pro,” according to DeWitt.
Choosing a product
Weed barrier comes in three basic forms: woven, needlepunched and heat-bonded, with hundreds of varieties possessing their own properties and applications. Learning how each of the fabrics can be used benefits your customer and business.
“Different fabrics have different water flow characteristics—from plastic with zero water flow to polyesters that have water flow characteristics of more than 200 gallons per square foot. For most applications, landscapers work with fabrics that are in the 15 to 20 gallons per square foot range,” says Gambla.
Weed barriers can be installed any time of the year, either prior to initial installation of the plant material, or as a retrofit. If you lay the geotextile on the ground around the plants, it will keep the weeds from sprouting. Weed seed will germinate under the surface of the soil. As it begins its upward climb, it will hit this barrier of geotextile. As long as no holes are punched in the landscape fabric, the weed will not penetrate it, therefore suppressing the weed from growing.
Site prep is crucial when installing landscape fabrics. For weed barriers, it is important to pre-weed and level out the ground’s surface, removing any debris that could puncture the fabric. Use a pre-emergent pesticide to kill any residual weeds.
Install your weed barrier “nice and tight and use longer pieces so you don’t have to worry about snagging it with your rake later on,” says Stanek. To insert plants, simply slice an “X,” folding back the corners to make the hole, insert plants and then tuck the fabric close to the plants, and secure with a pin.
Careful planning is necessary when applying a barrier to preexisting beds. “You want to plot out your holes and cut them small enough so that you can get the fabric over the plant and still maintain the fabric’s integrity,” says Blanchford.
Once the fabric is installed, you want to get it covered up. The biggest enemy to landscape fabric is ultraviolet rays. Some fabrics contain UV properties and are designed to handle a limited amount of sunlight but the more sunlight a weed barrier is exposed to, the sooner it will need to be replaced. “Weed barriers also reflect sunlight; the glare can burn some plants,” says Blanchford.
While weed barriers can be used in hundreds of applications, there are a few situations where it shouldn’t be used or where additional prep is required: establishing English gardens, which require reseeding, or if you plant lots of annuals that require frequent replacing.
“We discourage the use of weed barriers for frequently-replaced small annuals, because it requires too many holes and reduces the effectiveness of the fabric,” says Monson. “It’s easier to just heavily mulch areas like that and save the barrier for larger areas with plants that are replaced less frequently,” she adds.