While there are appropriate uses of these products in the landscape, too often they are used in ways that not only fail to control weeds, but cause other problems as well. This anecdotal story illustrates how good intentions can result in a landscape fabric nightmare.
A couple of years ago, when I was house shopping, my realtor showed me a property that she thought just might meet my horticultural needs. I knew the moment I saw the healthy populations of sow thistle, wild garlic and dandelion sprouting through the mulch between widely spaced junipers, that the steep bank along the front of the lot was going to be trouble. But the large, flat backyard was perfect for vegetable gardening, and the sunny front and side yards provided excellent sites for flower beds, peach trees and blueberries. I bought the house, and thus began my battle with old landscape fabric.
I am sure that the previous owners had the best of intentions, and followed then-current recommendations, when twenty years ago they scraped away the topsoil on the steep bank fronting the lot, layered on landscape fabric, planted junipers, and then covered it all over with mulch. Voila--stabilized bank, tidy shrubbery, and no weeds! And it probably worked reasonably well for a number of years. But even as the junipers thrived, the mulch decomposed and weeds began to establish, pushing their roots through the landscape fabric.
By the time I became the steward of the steep bank, this landscape installation was failing in nearly every way. While the junipers remained healthy, too few were planted originally, leaving large expanses of mulched area between them. The mulch had become a fine powdery peat-like substance that dried out and slid down the face of the landscape cloth toward the storm water ditch at the bottom of the hill,exposing the ugly landscape fabric. The flimsy plastic edging that was supposed to support the mulch at the bottom of the hill sagged and buckled. And the weeds? Never ending waves of spurge, crabgrass, sow thistle, Canada thistle, and chickweed.
At first, I got out there and pulled weeds by hand. But every footstep caused mulch to slide off the landscape cloth toward the ditch, so I ending up standing on the junipers (not a recommended practice). Weeds that had rooted through the landscape cloth were almost impossible to pull out. And even if I got all the weeds pulled, within a week or two a new crop would spring up. Next, I tried spot spraying glyphosate. That worked for very small weeds growing well away from the junipers.But I still had to hand weed plants growing up through the junipers, and also remove larger dead weeds, as they are nearly as unsightly as living weeds. And glyphosate did nothing to stop new weed seedlings from germinating. Pre-emergent herbicides would have been the next step, but after two years of battling weeds, I decided to attack the root problem.
This spring I purchased forty bags of mulch, hired a strong young friend, and declared war on the landscape fabric. Over two days, we replaced the sagging plastic edging with sections of stiff edging, properly staked, at the bottom edge of the bank. Balanced on the side of the slope, we raked off the old mulch, cut away large swaths of soggy, rotting landscape cloth using utility knives, machetes, hardware scissors, and any other sharp tool we could find. To call what we found underneath the landscape fabric "soil" would be a stretch; "moist pottery" would be closer to the truth. Nevertheless, it was populated with earthworms, so we covered it all over with new mulch and hoped for a biological miracle. The old landscape fabric was stuffed into the empty mulch bags and set out with the trash. I ached for days afterward.
I know I'm not finished rehabilitating the steep bank, but I think the landscape cloth nightmare may be over. I'll probably be cutting and removing escaped pieces for several years as edges work their way to the surface. But now I can stand on the bank without pushing the mulch off the slope. I can plant more junipers to fill in the open spots, apply herbicides safely and appropriately, spread more mulch, and pull the weeds that still make it through.
Dr. Linda Chalker-Scott, Washington State University, sums it up well in The Myth of Landscape Fabric:
- Landscape fabrics are not effective weed control solutions for permanent landscapes;
- They will eventually cause maintenance problems in terms of appearance, weed control, and landscape plant health;
- Organic mulches are preferred for permanent landscape installations.