Landscape material, even the most effective kind, was developed for the nursery industry. How do you keep weeds from growing between 5000 Delaware azaleas that have to be watered? Landscape fabric is the answer. Do they cover it with mulch? No. Why? Mulch turns to dirt which is a good medium for weed seed germination. Nothing prevents weeds entirely, especially if it's covered in organic material that aids in seed germination. What I "love" is redoing a bed that has had fabric put down and it's all full of roots and/or it's degraded so it comes apart in your hands and you're picking little pieces of black junk for days depending on the bed size. The fact that these companies guarantee no weeds for up to 20 yrs (in some instances) is just pure marketing BS. No LCO will guarantee weed free beds for 20 yrs (you'd be insane) using the 20 yr fabric, so why use it? You know why, it ads to the bottom line.
