Barbara Fair is a landscape extension specialist at North Carolina State University.

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The Lowdown on Mulch
by Barbara Fair       #Landscaping   #Misc   #Soil

Mulching your landscape not only helps retain moisture and provide insulation for your plants, it also helps define areas of the garden.

You may be wondering, why write an article about mulching? Everyone knows how to mulch, right? You buy mulch and place it around your plants. True, it’s not rocket science, but I have seen enough bad mulching jobs that it does merit more attention.

For years horticulturalists and arborists have provided information on how, when and why to mulch, and yet I still see “volcano” piles around trees. By no means is mulching a requirement for good gardening, nor is it used worldwide. Very few places in Europe actually mulch, and I have seen some spectacular gardens there. However, in this country it is a staple in almost every landscape.

Many commercial plantings use the red-dyed wood chips. These are tested just like other bagged mulches. Producers must have an MSDS (Material Safety and Data Sheet) to accompany the dye to ensure it is safe for animals and plants. This really makes the landscape pop, but it’s a little too much for me.

Getting the Right Materials
Everyone always asks me what type of mulch to use. Personally, I prefer quality triple-shredded hardwood bark. You may prefer something different. Many commercial sites prefer red-dyed wood chips. I do not care for this look, but landscapers tell me it is economical, long lasting and easy to get.

You can buy mulch just about anywhere, but certainly look for a reputable source. The Mulch and Soil Council (MSC) is a trade organization that has the largest volunteer certification program of its kind in the United States. Home Depot and Lowes require that their bagged products are certified. The Department of Horticultural Science at NCSU is home of the Horticultural Substrates Laboratory, where testing is done. Dr. Bill Fonteno and his staff have been testing mulches for over five years in cooperation with the MSC. They verify that labels are accurate, ensure weight and volume is correct and test for heavy metals. With over 2 million bags certified, it is easy to find something good for your yard.

Even though pine straw is light and airy, this mulch is piled too high on the trunk, forming the mulch “volcano.” • Currently the MSC can only certify bagged products, but is working towards the certification of bulk mixes. • Here in the Vatican Garden in Rome, like much of Europe, you do not see any mulch around the trees or in planting beds. It does not seem to keep plants from growing!

Anytime is fine to apply mulch, but most landscapers apply it in the spring or fall every year. Make sure if you apply new mulch every year that the depth never exceeds 3 to 4 inches on woody plants and 1 to 2 inches on perennials or annuals. You can often just fluff up last year’s mulch to make it look good, or even apply a thin layer to the old mulch to “spruce” it up.

You need enough mulch to help prevent weeds, moderate soil temperatures, hold in moisture, prevent erosion and of course, to look good. A proper application of mulch in the fall can help minimize heaving of newly planted perennials.

Remember mulch is a tool, and if used properly can be a part of developing a sustainable, water-wise landscape.


A version of this article appeared in Carolina Gardener Volume 23 Number 7.
Photography courtesy of Shannon Pable, Barbara Fair, and Gerald Klingaman.


Posted: 08/28/17   RSS | Print


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