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Ah, spring is in the air. If you’re like me, you are itching to start working in the yard again, soaking up the sunshine and fresh air.
One of the best things you can do for your landscape this spring is to apply mulch. And right now, when the soil has thawed but before the heat sets in, is the perfect time to get to work.
Why Mulch?
Mulch does much more than just make your landscape look good. It regulates the soil temperature, protects plants from damage and adds valuable nutrients to the soil as it breaks down.
While applying mulch properly can do wonders for the health of your plants, improper mulching can do more harm than good; it can even kill your plants!
How You’ve Been Mulching All Wrong
Over-mulching
What Is It?
Over-mulching is one of the most common mistakes people make, and it can have serious consequences for your landscape. You don’t need more than two to three inches of mulch, with another inch added each year.
Why Is It Bad?
Excess mulch makes it difficult for roots to breathe, leading to oxygen starvation of the entire plant. When oxygen levels drop, the plant becomes stressed. Trees and shrubs that are stressed are much more prone to attack from pests like insect borers and bark beetles. Over-mulching can also contribute to fungal and bacterial diseases.
Volcano mulching
What Is It?
Volcano mulching is another common and unfortunate mistake that can kill your trees. The tree’s root flare – where the roots start and the trunk ends – should be kept clear.
Why Is It Bad?
Piling mulch against the trunk of a tree (or stem of a plant) creates a perfect environment for diseases and pests looking for an entry point. Trunks and stems, unlike roots, don’t have the ability to survive in oxygen-deprived and damp environments. Once a tree’s inner bark is compromised, its roots become weak and unable to efficiently take in nutrients and water. If this continues for enough time, the tree will die.
“Hot” Mulch
What Is It?
Mulch that is too “hot” just means that it hasn’t had time to decompose. Fresh, uncomposted mulch – like grass clippings, for example – needs time to break down before being applied to your landscape.
Why Is It Bad?
While it’s true that properly decomposed mulch adds a host of nutritive benefits to the soil, hot mulch can do the opposite, actually causing nutrient deficiencies and toxicity. If the mulch hasn’t properly decomposed, microbes in the soil will steal existing nitrogen to break down the mulch, which can starve your plants of needed nitrogen.
Mulch That’s Too Acidic or Alkaline
What Is It?
Most of us don’t give much thought to the soil pH in our yard, but it matters a great deal to our trees and shrubs. Some mulch materials are naturally more acidic (like pine bark, pine needles and peat moss) while others (such as hardwood bark mulch) cause the soil to become more alkaline over time.
Why Is It Bad?
Know what soil pH your plants prefer. Acidic mulch works well for shallow-rooted, acid-loving plants like azaleas and rhododendrons, but can cause other plants to decline. Do some research (or ask your local garden center) to determine what kind of mulch your landscape needs to thrive.
Sour Mulch
What Is It?
When finely shredded mulch has been piled too high, the center of the pile can become anaerobic, or lacking proper oxygen. When this happens, microorganisms within the pile produce extremely acidic pH levels, not to mention a foul odor.
Why Is It Bad?
Sour mulch usually only occurs in very large mulch piles typically found in commercial or community operations. If the mulch smells bad, don’t use it. Sour mulch is extremely toxic to plants.
Mulching Too Close
What Is It?
While it may be tempting to mulch around the perimeter of your home, you should never apply mulch up against wood surfaces or the foundation of any structure.
Why Is It Bad?
One word: termites. Subterranean termites live in the soil and feed on wood products, like wood mulch. While it’s rare for mulch from a garden center to be infested with termites, they can be drawn closer to homes if mulch is readily available near the foundation. The rule of thumb is to leave at least a six inch unmulched gap around the perimeter of the home.
Mulching During the Wrong Time of Year
What Is It?
Mulching in the fall before the ground freezes can cause problems. The best time of year to spread mulch is in the spring, once the ground has thawed.
Why Is It Bad?
In the late fall, all of the little critters in your yard will be looking for a home to nest down in and keep warm during the winter. Mulching during this time provides a place for pests to settle down and multiply in your yard.
Mulching is truly one of the best or worst things you can do for your trees and shrubs. Avoid these pitfalls, and you’ll be providing your landscape with the extra boost it needs to stay healthy and beautiful all year long.
About the Author
John Lang is a Certified Arborist and a member of the Friendly Tree team, a family-owned New Jersey tree care service, dedicated to the thoughtful and careful maintenance of your trees and shrubs. Friendly Tree Service has been in business for 26 years and remains passionate about trees and nature. With a highly trained staff that treats every property as their own and state of the art equipment, Friendly Tree is on the cutting edge of the art and science of Arboriculture.