Landscape Fabric: Why Not?
Landscape fabric, otherwise endearingly known as weed fabric is one of those things that get us landscape professionals up in arms. Yes, it does prevent weeds (but only for a time). Yes, we use it but only in one main application. Throughout this post, I hope to eliminate some of the misconceptions about landscape fabric and give some excellent alternatives.
One Useful Application
Landscape fabric is really only good for one application. This is when you want to use stone (such as river stone or decomposed granite) instead of mulch. We’ve installed a good bit of river rock in some of our landscape jobs and we always use a geo-textile landscape fabric that allows some water penetration. The reason why?It does provide a weed barrier but it also prevents the stone from sinking and disappearing into the soil below. We have had pretty good success with this method. However, weeds will still grow from time to time (especially as time goes on and the rock breaks down which takes quite a while and the debris gather from plants, birds, etc.). So how is this different from placing mulch on top? That’s a good question which I plan to answer below.
Mulch + Landscape Fabric
Placing mulch on top of weed fabric pretty much defeats the purpose of the landscape fabric from the beginning for a few reasons:
Reason #1: Mulch breaks down (relatively quickly), creating enriched soil which lays on top of the landscape fabric. Weeds grow in soil – sometimes very little of it.
Reason #2: As mulch breaks down, a natural fertilizer is created for your ornamental plants – weed fabric impedes these nutrients from reaching the roots of the plants.
Reason #3: As weeds will grow on top of the fabric, they will also eventually penetrate the fabric. This makes removing and controlling weeds nearly impossible since the roots are both above and below the fabric. Essentially the endearing term, weed fabric, is quite accurate. Since weed fabric can cultivate the perfect environment for weeds to get established and stay.
Your ornamental plants need nutrients, water, and air in and around their root systems to be happy. We like happy plants (insert Bob Ross’s voice). Landscape fabric suffocates roots over time, causing an excess of surface roots to develop, often growing through the fabric.
The other drawback to fabric is girdling roots – surface roots that circle the plant’s root flare as the trunk grows – that cause a strangulating affect. So when you go to remove a stressed, girdled plant (a Viburnum, in the photo below) years later you end up with a rootball the size of a refrigerator. Plus the fabric itself can become the very thing to strangulate the plant. Fabric does not generally move much once it is staked or stapled in place but the plants do. Plants will continue to grow and expand over time. When a stationary object is within the growing limits of the trunk or stem, the plant will grow around or over the object. In the case of fabric, it will essentially cut off the supply of water and nutrients as the plant continues to grow. This also increases the probability of detrimental disease and insect damage due to openings around the wound.
So if your thinking of re-doing your landscape yourself, think again before using that big box store’s recommended method of weed fabric and mulch! If you are thinking about using a contractor to install your landscape and they recommend weed fabric under your mulch, I ask you to re-consider your contractor and… maybe give us a call instead?
If you have landscape fabric already and decide to re-vamp your landscape, I recommend removing the fabric to the best of your ability. You will have a healthier landscape in the long term. Besides, your landscape professional will thank you because we pretty much loathe the stuff!
Beyond all of the items I’ve talked about above, landscape fabric is ugly when it starts to show, difficult to cover up, and it’s tough to plant in too!
Good alternatives to use instead of weed fabric include Preen or another pre-emergent herbicide, spot treatment of round-up or vinegar mix, corn-gluten, newspaper, cardboard, and good old fashioned hand-pulling.
There are some disclaimers I should put in here…
When using an herbicide such as Preen, make sure to check the label for plants that can be affected by the product. Also, make sure to apply the product based on the rates on the container. In this case, more is not better…and yes, this goes for Round-Up too!
And speaking of Round-Up, be very careful around ornamental plants that you don’t want to damage as a slight breeze can drift the product on to desirables. I recommend using a milk jug with the bottom cut out of it to contain the spray overtop of the weed.
You can also use a vinegar solution (there are many out there to try) to kill most weeds. It doesn’t work quite as well as Round-Up but is a less chemically based option. The same disclaimers from above should be noted for this mix.
Corn gluten is a natural pre-emergent. I have heard this works but not as well as the chemical options. This is generally more expensive than Preen but is a good substitution (especially for those who don’t care for the chemical applications).
Newspaper and cardboard are both readily available bio-degradable items that prevent weeds from coming through as easily. Generally, I’ve seen this recommendation at 1/4″ thick layer of newspaper and then a good layer of mulch. This method is a bit labor intensive but for those of you who rather not use chemicals, it’s a good option. On the plus side, it’s normally free too!
So in the end, don’t waste your time or money on that fabric unless you are installing river rock or other stone as mulch. Keep your landscape healthy and weed free by using the alternatives I’ve listed above. You’ll be very happy in the end when your landscape investment lasts!