As a follow up to my last column on organic mulches, I will discuss inorganic mulch. But before I get to that, I want to expand on my comment regarding “mulch should not be piled up on the tree.” As you travel around, especially in parking lots, you will notice what is referred to as “mulch volcanos.” One to two feet of mulch stacked onto the tree may look attractive but the bark of the tree retains moisture. That haven of moisture is an invitation to insects as well as disease.
Inorganic mulch may be natural stones, pea gravel, crushed stone, lava rock, marble chips, shredded tire chips or man-made plastics. Inorganic mulches provide many of the benefits of organic mulch. Erosion is reduced, moisture is conserved and roots are protected. However, one major difference is that inorganics do not decompose and deliver organic matter to the soil. Soil organic matter is essential to the overall health of the soil.
Inorganic mulches do have certain advantages over organic mulches. Although the initial cost is higher, inorganic mulches do not need to be reapplied as often as organic mulches reducing the overall lifecycle cost. Inorganics such as natural stones have a more formal look which is appealing to many gardeners. Shredded tire chips are a recycled product and come in a variety of colors.
Inorganic mulches are good choices for pathways and buffers between the lawn and driveways, sidewalks, and patios. If you choose inorganics, specifically stone, it is critical that a porous fabric be placed on the soil and below the stone. The fabric will prevent the stones from migrating into the soil. Migration is not just downward but sideways as well. It is also critical to install edging such as steel or a sturdy plastic. One final thought on stone: Once it is in place it can be extremely difficult to move so do your research.
No matter what mulch you choose, consider whether you are trying to blend, complement or contrast it with your home and existing landscape.
Larry’s timely tip: Fall fertilization is critical for cool season grass lawns such as fescue. If you fertilized just once when you seeded you will need to fertilize again. Talk with your full-service garden center staff for the correct fertilizer blend.
Have a safe and Happy Thanksgiving!
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