What Is the Purpose of Mulching and 8 Common Mulching Mistakes to Avoid

Few materials are as beneficial for your garden or as misunderstood as mulch. And although it is widely recognized as a valuable addition to any landscape, not everyone knows why. So this article will provide you with answers to questions such as, “What does mulch do?” and “What is mulch used for?” You can reap the benefits of mulch and have the landscape you always dreamed of. We will also discuss the most common mulching mistakes.

What Is Mulch?

Mulch is defined as any organic or inorganic material that is placed atop soil in a garden or flower bed or used in landscape design. While there are a number of different types and varieties of mulch to choose from, not one variety can do it all, so it’s important to choose a material that will suit your exact needs based on location, plant type, soil, and more. Options include:

  • Organic – Because organic mulches are made from natural materials they decompose over time adding valuable nutrients to the soil.
  • Bark – Wood chips are ideal for use in perennial beds or around trees or shrubs and can be a decorative addition to any landscape. Pine is slightly more acidic than other varieties making it a strategic addition for plants that require a more acidic environment.
  • Compost – Nutritionally dense compost can be used as a standalone mulch or as a healthy boost to plants, providing a continuous supply of nitrogen and carbon. Because it decomposes quickly you can expect to add additional layers of this material each month during peak growing season.
  • Lawn Clippings – While they can be an effective weed suppressant, grass clippings should be used sparingly as they can emit an unpleasant order, prevent the transmission of water, or mat if the layer is too thick.
  • Shredded Leaves – Leaf mulch is attractive to earthworms and is a great way to dispose of the leaves on your property. Because it is a less attractive alternative you may want to reserve the mulch for less formal areas of your garden.
  • Straw – A layer of straw can help to retain moisture, inhibit weed growth, attract insects, and deter birds and rodents. It decomposes slowly and can last through the growing season.
  • Inorganic – Inorganic mulch is a long-lasting alternative that can inhibit the growth of weeds, although it provides no nutritive value to plants or soil.
  • Landscape Fabric – In areas of inactivity or where the soil doesn’t require fertilization, landscape fabric provides a beneficial barrier against weeds, though it can also prevent the passage of water and vital nutrients
  • Stones – Ideal for areas that require assistance with drainage or heat retention.

What’s The Purpose of Mulching

There are many different reasons to use mulch in your landscape.

To Suppress Weeds

Weeds are always encroaching on your plants. They are a burden for gardeners because they often require careful monitoring. If you do not regularly pull weeds from your garden and flower beds, you can end up with an overgrown, messy area that is suffocating the growth of your plants. Thankfully, mulch can help you avoid all that.

In order for weeds to grow, they need sunlight and space, just like regular plants would. By mulching the area around your plants, you keep the weeds from getting the necessary nutrients that they need from the sun to grow. To retain this benefit, it is critical that you mulch on a regular schedule. Because organic mulch is biodegradable it will eventually break down. This gives weeds the opportunity to grow. However, if you can maintain a nice layer of mulch on your plant bed, you will keep this from happening.

To Enrich the Soil

The very same thing that makes you have to replace the mulch regularly is the same thing that keeps your soil rich and fertile. Because organic mulch decomposes over time, it provides the soil beneath it with nutrients and additional texture that can improve the growth of your plants. This means that organic mulch continues to benefit your plants even after it is no longer viable in its original state, which makes it doubly useful.

To continue enriching your soil and keeping your garden and plants fertile, you will want to replace your mulch at least once a year. You will know when it is time by the appearance of the mulch. For instance, mulch can fade in color after prolonged exposure to sunlight or you can begin to see patches in your garden bed where there was once densely packed mulch.

To Retain Moisture

Watering plants can seem like a chore, but mulch can help you with that too. This is because mulch can help to retain the moisture from regular waterings and keep the sunlight from evaporating the water too quickly. Ultimately, this means that you don’t have to water as frequently which saves you both money and time.

Of course, not all mulches are going to have the same effect at retaining water. For instance, organic mulches are better at keeping water in the soil and preventing the sun from hitting the soil directly. That said, there are other types of mulches, like rubber mulch or stones, which only have the benefit of allowing the water to pass through the soil but have no effect on retention.

To Regulate Temperature

Think about the insulation you have in your home. It keeps your house warm during the cooler months and it keeps the air conditioning from escaping during the warmer months. That’s what mulch does for plants. Because rapid fluctuations in temperature can be harmful to plants, mulch acts as an insulator that limits the fluctuations in temperature from being too extreme. This is especially helpful when hotter temperatures keep water from being fully soaked into the soil.

To Prevent Erosion

Without the protection of mulch, soil is left to the elements. While this is not always damaging, it absolutely can be if you are dealing with high winds or excessive rainfall. In these instances, mulch does the job of acting as a shield for the soil. It keeps the harsh weather from eroding the soil and diminishing its fertile properties. With enough time, eroded soil can be damaging to plants, so it is important to keep the soil protected before it gets to the point of no return.

Common Mulch Mistakes to Avoid

Want a healthier yard? Stop the mulch madness. Learn the best and worst mulch for your plants and avoid these 8 common mistakes to make the most of your mulch.

1. Avoid Building Volcanoes

In order to grow, trees need oxygen as well as nutrients, water, and light. What they don’t need is suffocating piles of shredded bark at their base. Mulch volcanoes deprive roots of air, prevent trees from getting the water they need, provide a haven for pests, and encourage disease.

So why do people pile so much around their trees year after year, creating mulch volcanoes? Perhaps they like the way a giant cone of mulch looks, or maybe they see the volcano as a way to protect tree trunks from weed eater damage. Whatever the reason, mulch volcanoes are a bad idea. An even spread of one to three inches of mulch however, is a great way to promote tree growth.

Mulch should extend out to the tree’s drip line. Not only will that protect the trunk from mower and trimmer damage, but it will also eliminate the tree’s competition with turf for moisture and nutrients. Best of all, a two- to three-inch layer of mulch that extends to the drip line will help rather than hinder the tree’s growth, well-being, and longevity.

2. Don’t Miss the Drip Line

What’s a drip line? When it rains, water drips off the tips of the outermost limbs of trees. Image drawing a line around the tree right below those tips. That’s the drip line. Most of a tree’s small roots are located there rather than at the base of the trunk.

3. Don’t Apply Mulch in Layers That Are Too Thick

Depending upon their type, loose mulches should be applied in layers one- to three-inches thick. Applying almost any mulch too thickly can result in the same problems that occur when plants are “volcanoed” (see above).

Base your layer thickness on the following guidelines.

  • One-Inch Layers – Lava rock, river rock, stones, gravel, and sawdust (aged one year minimum) should be applied in one-inch thick layers.
  • One- to Two-Inch Layers – Spread compost and grass clippings in layers of one to two inches.
  • One- to Three-Inch Layers – Wood chips (aged one year minimum) are best applied from one to three inches thick.
  • Two- to Three-Inch Layers – Shredded leaves, pine needles, and shredded bark work best if applied in layers two to three inches thick.

4. Don’t Use the Wrong Kind of Mulch

Are you using the right type of mulch? All mulch isn’t the same; some work best for certain plants, trees, or shrubs. For example, like sawdust and wood chips, shredded bark is a poor choice for an herb garden and will cause plants to wilt. Neither should it be used in a vegetable garden.

Which mulch is best for your plants? While different geographical locations sometimes use different types of mulch, follow these basic guidelines for best results.

  • Blueberries: Best – Sawdust, compost, pine needles, and/or bark. Worst – Mushroom compost (has high ph).
  • Herbs: Best – Organic matter and/or white gravel. Worst – Sawdust or wood chips.
  • Small Fruits (such as strawberries & grapes): Best – Straw, sawdust, shredded leaves, grass clippings, newspaper, compost. Worst – none
  • Azaleas & Rhododendrons: Best – Pine needles and/or bark. Worst – Mushroom compost.
  • Tomatoes & Peppers: Best – Red plastic or organic matter. Worst – Wood chips or shredded bark.

5. Don’t Mulch Everything

Mulch really is great. As we’ve seen, it suppresses weeds, conserves moisture, and more. But that doesn’t mean gardeners should use the same mulch (such as shredded bark) throughout their landscape. Not only should gardeners avoid using the same mulch throughout their landscape, but they should also consider leaving some soil either lightly mulched or completely free of it in order to provide a home for ground-nesting bees, which pollinate fruits, vegetables, and flowers.

6. Don’t Mulch at the Wrong Time

It’s best to mulch when the ground is damp. Perennial herbaceous plants (plants that die in winter and come back in spring) should be mulched in late fall to protect them from the freezes and thaws of winter.

7. Don’t Use Old Mulch

When spring arrives, mulch that was used to protect plants over the winter should be removed.

Mulch on spring bulbs like daffodils, hyacinths, crocus, and tulips should be brushed off in early spring. If left on bulbs, their new shoots may be pale or even colorless. They may also break. Likewise brush mulch away from perennial plants. Mulch that’s piled heavily on their crowns could lead to rot. If voles (small, mice-like rodents) are a problem, avoid mulching the crowns entirely, especially on small fruits like blueberries and blackberries.

8. Avoid Dirty Mulch

Pest-free mulch that does not stink is the best kind to use. Mulch that has a chemical smell (such as sawdust and/or wood chips that have not been aged) should be avoided. Also, mulch that’s teeming with ants or other insects should not be used, particularly if it will be applied around foundation plants or other plants near your home.

Our favorite mulch at Low Country Style and Living is compost which we make ourselves. Compost has all the advantages of mulch and can be used in place of chemical fertilizers. Over the course of the growing season, worms gradually work the compost into the soil adding much needed nutrients.

Mulch is a multipurpose tool used by gardeners to enhance the beauty of their landscapes and control weeds, reduce the need for water, and moderate the temperature of the soil. You can purchase it or make it yourself. Either way, your garden will thank you.

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