Is landscape fabric a good way to control weeds?
The use of landscape fabric inspires strong opinions from many gardeners. Some love it because it significantly reduces the amount of time they spend weeding while others despise it because in addition to reducing the number of weeds, it also creates an ecological imbalance, negatively impacting everything from insect lifecycles and bird feeding habits to the natural decomposition of organic matter.
When used around plants, landscape fabric causes trees and shrubs to form shallow roots, greatly increasing their susceptibility to drought and heat stress. It also interferes with evaporation, increasing the chances of mold and root zone diseases. In addition, roots tend to become entangled in it, which is neither good for the plant nor the fabric. And, as the fabric breaks down, it leaves bits of synthetic material in your soil.
If you haven't guessed, I don't like the stuff. However, it's preferable to nuking your weeds with chemical herbicides and that tends to be the direction frustrated gardeners head when they've finally had it with that one area of their property that will never, ever amount to anything more than a weed jungle.
When contemplating the use of a permanent barrier, it's helpful to know the difference between landscape fabric and landscape plastic (aka plastic mulch).
Landscape plastic consists of long sheets of nonporous black plastic that looks pretty much like an unbroken swath of garbage bags. Not surprisingly, it prevents the transmission of light, air and moisture and is gleefully antithetical to living things. It's used in places where you want a complete suppression of all things green, such as under decks, porches, walkways, river rocks or crushed stones. It should be avoided in areas where the roots of trees, shrubs or other perennial plants are found.
Landscape fabric, on the other hand, is woven from laminated materials and although it's more expensive than landscape plastic, it allows water and nutrients to pass through it, albeit not as freely as they would if the fabric wasn't present. This is preferable for controlling weeds around shrubs, trees or other permanent plantings, but still comes with the caveats mentioned above.
Both landscape fabric and plastic are usually covered with organic mulch or crushed stones, both to slow the breakdown of the material and to hide the fact that ladscape fabrics and plastics are rather ugly. Over time, weed seeds will be deposited on top of the fabric layer. However, the resulting weeds won't be deeply root and are fairly easy to pull out.
