Applying a layer of mulch over your tree’s root zone is one of the easiest and most effective ways of supporting your trees. When properly applied, mulch provides a variety of benefits that will not only help keep your trees looking their best but also better equip them to fight off pests and pathogens.
But not all mulches are created equally; some are very helpful for trees, while others fail to provide many benefits at all. Some mulches can even be harmful to trees.
We’ll try to help you identify the best kind of mulch for your trees and share some tips for getting the most out of your mulch below!
The Benefits of Tree Mulch: How Does Mulch Help Trees?
The specific benefits tree mulch provides vary a bit based on the way the mulch is applied, the type of mulch used, and the environmental conditions in your area. But generally speaking, mulch provides the following benefits to trees:
- Moisture Retention: Mulch helps to trap moisture in the ground and slow the rate of evaporation. This is especially helpful for supporting trees during our long, hot, and dry Oklahoma summers, and it reduces the amount of supplemental water you’ll need to provide.
- Temperature Regulation: Mulch also helps to protect tree roots from extreme temperatures, as it keeps them cooler under the hot summer sun and warmer during sub-freezing winter temperatures. However, some types of mulch (such as rocks) can actually create problems during the summer and cause soil temperatures to climb.
- Weed Suppression: Mulch helps to shade the soil, which usually helps to prevent or at least limit the growth of weeds and other undesirable vegetation. Aside from this direct benefit, it also means that you won’t have to spray herbicides or spend hours hand-pulling the weeds that would otherwise grow under your tree.
- Improved Soil Health: Organic mulches help improve soil health in a number of ways. For starters, they’ll release nutrients in the soil as they break down, and they’ll also help improve soil structure and reduce soil compaction over time.
- Lawn Equipment Protection: Lawn mowers and string trimmers can quickly cause damage to a tree’s trunk or roots, and this kind of damage often leads to potentially hazardous decay problems. But when you apply mulch around a tree, you protect the roots and trunk and eliminate the need to mow or trim in the area at all.
- Aesthetic Appeal: Many homeowners find mulch beds very attractive, and they can create a manicured look that your neighbors will envy. Just be sure that you don’t make aesthetic decisions (such as selecting dyed mulch) that will negatively affect your trees’ health.
Four Common Tree Mulches Oklahoma Homeowners Should Use
A quick trip down the aisle at a local home improvement store or garden center will reveal countless varieties of mulch marketed for use under tree canopies (and other applications). But most of these individual products will fit pretty neatly into one of four categories.
All of these mulch types are broadly helpful for trees and represent good choices for Oklahoma homeowners.
1. Wood Chips
“Wood chips” typically consist of fairly coarse chips derived from tree branches, leaves, and small trunks, which have been ground up in a wood chipper. Wood chips may be from just about any common tree species, but they’re most commonly made up of common local trees — pines, oaks, maples, and others, in our region.
Wood chips are one of the more affordable and beneficial tree mulches, and you can sometimes obtain them for free from local tree care services and landscapers. However, they don’t offer the “polished” aesthetic that some other mulches do.
2. Bark Nuggets
Bark nuggets are like wood chips, except that they are made solely (or primarily) from the bark of dead trees. They also tend to be ground more finely and have a more uniform appearance. You may find bark nuggets from a variety of species, but pine bark nuggets are among the most common.
Bark nuggets are generally more expensive than many other types of mulch, but they often look fantastic when properly applied around trees.
3. Pine Straw
Pine straw is the term applied to the needles that pine trees shed. You may be able to source your own pine straw if you have a number of pine trees on your property, and they’re generally less expensive than bark nuggets when purchased commercially.
Pine straw is quite effective for mulching sloped areas, as it tends to stay in place better than bark or wood chips. However, it may acidify the soil over time, which can be a good thing or a bad thing, depending on the tree species you have in your yard.
4. Dead Leaves
Dead leaves — whether left whole or shredded — can be an effective mulch for trees. The leaves will contribute organic matter to the soil and help reduce soil compaction, and they’ll also help retain moisture and reduce the need for supplemental irrigation during the summer.
Many homeowners can source dead leaves for free by simply raking or blowing the leaves covering their property in the autumn. But they don’t last very long, as they decompose rather quickly. They may also blow away in windy areas, and they rarely provide the aesthetic appeal that some other mulch options do.
Two Common Tree Mulches Oklahoma Homeowners Should Avoid
Any of the four mulches discussed above can work well for Oklahoma trees. However, there are two mulches that fail to provide many benefits and may actually cause harm to your trees. Accordingly, homeowners in Oklahoma should avoid the following two kinds of mulch.
1. Rock or Gravel
Rock and gravel “mulch” is often prized for its appearance, and it does provide a few benefits to trees. For example, it will protect your trees’ roots from mower and string trimmer damage. It may also suppress weed growth under the tree canopy.
However, rocks and gravel are heavy, which can lead to soil compaction. They also tend to heat up in the summer sun, which can kill your trees’ roots, and they don’t contribute any organic matter to the soil.
2. Rubber Pieces
Small rubber pieces are sometimes used as mulch, but these materials present a number of problems. For starters, they may leach harmful chemicals into the soil, which can harm your trees as well as the other plants or groundcovers you’re trying to maintain.
Additionally, rubber pieces fail to provide any organic matter to the soil, and they rarely look attractive (let alone natural). Finally, rubber pieces may actually float away during rainy weather, which can lead to clogged sewers and runoff grates.
Mulching the Right Way: Mulching Tips for Homeowners
In addition to selecting one of the best kinds of mulch for your trees, it’s also important to apply the mulch properly. This is the only way to ensure your trees get the maximum value from the mulch, and it’s also important for preventing the serious harm improper mulching can cause.
- Spread the mulch across as much of the root system as possible. Most tree roots spread far and wide, extending at least as far as the drip line (the edge of the tree’s canopy). For maximum benefit, you’ll want to ensure the mulch extends at least this far to protect the tree’s fine absorbing roots.
- Never pile mulch up against the trunk. Colloquially called a “mulch volcano,” a big pile of mulch packed up against a tree’s trunk is very detrimental, as it traps moisture and fungi near the bark. This often leads to trunk or root rot, which often causes trees to fail suddenly. Always leave a 3- to 6-inch mulch-free zone near the trunk.
- Apply a 2- to 4-inch-thick layer of mulch. The depth of mulch you spread over a root system is crucial for your trees’ health. If the layer is too thin, it won’t suppress weed growth or protect the roots. If it is too thick, it may prevent air and moisture from reaching the roots effectively.
- Place the mulch directly on the ground. Don’t place mulch on top of fabric or plastic barriers. Doing so is not only unnecessary (a thick layer of mulch will suppress weed growth on its own), but it will also prevent water and air from reaching the roots, which will severely stress your trees.
- Avoid dyed mulches. Dyed mulches may look attractive in some cases, but the dyes used to provide their intense color will leach out of the wood over time. In some cases, these dyes may harm your tree or encourage mold growth, which may disrupt the soil ecosystem and cause root damage.
Trust Elion Landscaping for All Your Tree-Care Needs
Mulch can help support your trees, but it’s not a magic bullet, either. You’ll still need the help of a professional arborist to ensure your trees are getting all of the resources they need to thrive.
That’s exactly what you get from Elion Landscaping. We provide an array of tree-care services, including installation, pruning, removals, and stump grinding. We can even source, deliver, and apply mulch for you! Contact us today to schedule an inspection and make sure that your trees have everything they need to live long, healthy lives.
