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Benefit of landscape fabric myth persists

Short-term gains don't outweigh negative growth consequences
Benefit of landscape fabric myth persists

Some lessons in gardening have to be learned the hard way, a case in point - the myth of landscape fabric.

I recently observed some new landscaping of large garden beds that were being covered with woven landscape fabric, then covered with two inches of bark mulch.

For many years I have tried to educate homeowners and gardeners on the incorrect use of landscape fabric. But still the myth persists that landscape fabric controls weeds in the garden. Arguably there is a short-term benefit in control and prevention of some weeds. However, several negative growth conditions occur in fabriccovered gardens. And the maintenance of fabric covered gardens is not lower than the alternative.

Landscape fabric works well for erosion control during construction and sometimes permanent cover for very steep slopes. Fabrics of various brands have been developed for floating islands, streamside protection and drainage use.

Fabric, or ground cloth as it is sometimes called, also provides long-term protection with low maintenance in nursery and greenhouse settings. Even agricultural use of woven row covers or crop covers can provide improved growing conditions and lower maintenance.

Beyond commercial or industrial use, landscape fabric works well for short-term use to protect soil during construction. Or it is meant to cover earth with a potted crop growing on top of the fabric. With no soil or mulch present, the weeds have nothing to grow in. The fabric works well as a tool for those uses. The incorrect technique of laying fabric and covering it with gravel, sand or rocks of some sort creates a slowly compressing and smelly mess that still grows weeds anyway. Rocks are a good matrix to grow weeds, especially in our rainy climate where seeds abound on the wind.

To make matters worse, landscape fabric does not control pernicious weeds like horsetail or morning glory. I have renovated many gardens with landscape fabric and found large networks of weed roots growing just under the fabric.

The roots grow under the surface of the fabric in search of air and water or holes to grow through. Holes are usually found where each plant is growing - the last place you want weeds. Landscape fabric has become so manufactured now that many brands do not allow positive air flow into the soil. And consequently less water reaches the soil, especially during drought. These are great conditions if you want to grow shallowrooted stunted plants that can't find a breath of life.

Problems with fabric use arise in gardens for several reasons. Firstly, there is the beautiful occurrence of garden change over time, and the fabric is a hindrance to that process. Few gardens remain unchanged over their lifespan and landscape fabric makes changing the design difficult and more expensive. Even minor plant replacements are more difficult with fabric in place.

Secondly, shallow rooting is a common occurrence for all plant roots growing under landscape fabric, even large trees and shrubs. I have seen 30-foot tall pine trees growing under landscape fabric. Pine roots as large as two inches in diameter were found growing just under the fabric.

Thirdly, weed-seeds can spread by wind, water, pets, people and machinery. There are peak times of the season where weed seeds are on the wind all day. The key understanding here is that all future weed growth will occur on top of the fabric. So no matter what soil or mulch cover is put on top of the fabric, weeds will still grow.

So what is the value of the fabric, especially when considering the other negative aspects of landscape fabric use? And let's not forget the financial cost to buy and install fabric.

No thanks, landscape fabric is not worth the problem it creates over the long term.

There are only two good options to prevent weed growth.

Grow plants robust, allowing all foliage to touch and cover earth, thereby crowding out weed growth.

Or, mulch the soil deep enough to prevent weed growth and maintain the mulch consistently over the life of the garden. For most gardens a combination of those methods will produce the most consistent beautification and manageable maintenance.

In average residential conditions, most gardens last 15 or 20 years, maybe 50 years if someone really loves the garden. During those years much change, development and growth of a sense of place occurs.

Fabric does not contribute to those virtues. Landscape fabric has specific uses but it has become a sales gimmick foisted upon misinformed consumers under the guise of trouble-free weed control.

Only a fabric-free garden can thrive to be beautiful.

Todd Major is a journeyman horticulturist, garden designer and builder, teacher and organic advocate.