Understanding mulch terminology

My last column provided you with some information on whether you may want to install mulch products in your yard or garden.
The terminology around gardening can be a bit confusing at times, never mind a topic like that of mulch. As such, this column will assist you in understanding the terms related to the types of mulch you may consider for your garden.
Some gardeners are confused by the terms “mulch,” “spring mulch,” and “winter mulch.” These terms are defined for you:
•Mulch
In general terms, mulch refers to the product applied on top of garden soils to offer protection throughout all or some of the seasons. When mulch is referenced in this column and others to follow, I am referring to mulch as an installation not necessarily disturbed or removed at the end of each season.
Vegetable garden mulching is an exception to this since it is carried out on a seasonal basis in our region.
•Spring mulch
Spring mulch is applied to gardens once the soil warms up in the spring. This is best if done after the last frost date to ensure adequate soil warmth for good plant growth.
This method is used to suppress weeds and conserve moisture, and can be applied to gardens that have plants you replace on an annual basis, like vegetables and annual flowers.
•Winter mulch
Doesn’t actually keep plants warm, but maintains a more even soil temperature during the end of the winter season.
Winter mulch provides plants extra protection when winter or early spring brings alternating periods of freezing and thawing, and where there isn’t enough snow cover to give plants a thick insulating blanket.
Winter mulch often is recommended for protecting sensitive perennials and shrubs in our region. It often is applied thickly at the base of a plant or shrub or right over the plant, covering it entirely for the winter season.
An example of this is covering rose bushes entirely with straw, leaves, or peat moss each fall and then removing all of the mulch each spring.
Also confusing to gardeners are the terms “organic” and “inorganic” when applied to mulch products.
Organic mulch refers to a mulch product that’s derived from plant material. Because it is derived from plant material, you will have decomposition of the product over time, as well.
Examples of organic mulches are sawdust, wood chips, bark, grass, straw, cocoa bean or coconut hulls, plant matter, etc.
Inorganic mulch, on the other hand, refers to a mulch product that is not derived from plant material. Be careful not to confuse the terms natural and unnatural with the terms organic and inorganic because gravel or stones occur naturally in nature but are not organic.
Other types of inorganic mulch products include carpet remnants, plastics, rubber sheeting, etc.
Many gardeners have heard the terms geotextiles and landscape fabrics, but are really unsure what they are and how they fit into the garden.
Geotextiles is the name given to a family of geosynthetic fabric products that are synthetically manufactured for use in projects that involve soil surfaces or soil materials.
These fabrics can be woven or non-woven, and come in a large variety of weights and textures all specific to certain applications. A geotextile is used for reducing erosion, acting as a particle filter, separating types of soils from each other, and providing a stable surface or barrier for applying a product on the soil surface.
Geotextiles are used in many construction projects all over the world. This can include road building, urban development, and bridge building, just to name a few.
In our region, the use of geotextiles is common in the construction of logging roads.
Geotextiles such as landscape fabric are derivatives from the industrial products used in the landscaping and gardening industry.
When using them in the garden, geotextiles should be non-toxic to vegetation, inert to common chemicals, and be mildew and rot resistant. Those products with UV protection and stabilization also are best for landscape use.
The rubber sheeting used for pond lining also is considered a geotextile, and should be graded as fish-safe if you are going to use it in a pond with fish and plants.
Landscape fabric, meanwhile, is a form of a geotextile that’s manufactured specifically for the landscape and gardening industry. The different types of fabrics available are woven, non-woven, or spun-bonded synthetic petroleum products.
These usually are dark grey or black in colour, and come in many different “weights” and thicknesses.
When laid out on the ground or soil surface around plantings, these products provide a physical barrier against weeds and tree roots.
Using a barrier for weed prevention is not new, of course. But prior to the development of geotextiles, the standard barrier for weed prevention was plastic, which prevents roots from getting essential water, oxygen, and nutrients.
Plastic also can keep roots too wet, leading to an increase in root-rot diseases.
Unlike plastic, landscape fabrics breathe, letting air and water through, and don’t adversely affect the health of plants. In fact, research has shown that trees and shrubs with landscape fabrics around them grow just as well as ones without fabric, yet without the same weed competition.
Before purchasing a landscape fabric for your project, be sure to read the label to ensure this is the right product for your application. There usually are recommendations on the packaging helping you to apply the right product for the right job.
Landscape fabric is an investment, so choose the right product to ensure you get the best value for your money.
I hope this column has eliminated any confusion you may have had about some of the terminology that’s commonly used when describing landscape and garden projects.
By clearly understanding these terms, you can look forward to the next columns in this series which will provide you with some more in-depth information on mulch and the installation of a mulch product.

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