Mulch is a popular way to spruce up flower beds and define the area between lawn and garden. It’s also used as a buffer, keeping moisture in soil longer instead of the sun baking the uncovered dirt dry. Mulching young trees certainly tidies up the area and helps hydration, but there are other benefits as well. Read on for more information on choosing the perfect mulch and best practices in application.
Why Mulch Your Young Trees
Mulching a young tree is beneficial because it helps retain moisture in the soil, regulate soil temperature, suppress weed growth and provides a source of nutrients as it decomposes and minimizes erosion. These benefits help the young tree establish its root system more effectively, grow more quickly and become more resilient to environmental stressors.
Moisture retention: Mulch helps retain moisture in the soil by reducing water loss through evaporation. This is especially important for young trees that have shallow roots and need to establish themselves in the soil.
Temperature regulation: Mulch acts as an insulator, regulating soil temperature and protecting the roots from extreme temperatures. Imagine the difference between cool, shaded soil and the Florida sun beating down on bare ground in July.
Weed suppression: Mulch helps suppress weed growth by minimizing the amount of light that reaches the soil. Weeds compete with young trees for water and nutrients by leaching them from the top surface of the soil before they can reach roots. While mulch helps, there are usually a few weeds that still make it through. Spot treat those with your weed deterrent of choice.
Nutrient cycling: As mulch made up of natural materials decomposes, it releases nutrients into the soil, benefiting young trees. The process is carried out by microorganisms such as bacteria and fungi, which feed on organic matter in the mulch. As they break down the mulch, they release nutrients such as nitrogen, phosphorus and potassium into the soil.
Erosion control: When rain falls on bare soil, it can create a hard crust on the surface, making it difficult for water to penetrate. This can lead to runoff and erosion. Mulch helps by minimizing impact and distributing moisture more evenly throughout the soil.
Which Mulch is Your Perfect Match
There are advantages and disadvantages of organic versus inorganic mulches. While each may find a use, the added advantage of nutrients being added to the soil during decomposition pushes organic to the front of desirable mulches for young trees.
Organic Mulches
Shredded Bark or Wood Chips
PRO – Provides long-lasting, attractive coverage and helps improve soil health by slowly decomposing over time and releasing nutrients into the soil. Also heavy enough to help prevent soil crusting and erosion.
CON – May attract pests such as termites or carpenter ants if not aged properly. Can also be flammable and pose a fire hazard in dry conditions if piled close to the home.
Leaves or Grass Clippings
PRO – An inexpensive and readily available mulch that provides good moisture retention and weed suppression.
CON – Can mat down and form a barrier that prevents water from reaching the soil. Can also harbor diseases or pests if not composted properly.
Compost or Manure
PRO – Can provide a high-nutrient, slow-release source of fertilizer for plants, while also improving soil structure and water-holding capacity.
CON – May have a strong odor, attract pests, or contain pathogens if not aged properly. Can also be high in salts and potentially harm plants if used in excess. Be sure compost and manure are properly aged so the heat of decomposition does not burn plants.
Pine Needles
PRO: An acidic mulch that can help acidify soil, making it ideal for acid-loving plants such as azaleas, blueberries and rhododendrons.
CON – May acidify soil to the point where some plants cannot grow. Can also be difficult to rake or remove once in place.
Cocoa Bean Shells
PRO – A decorative and fragrant mulch that can suppress weeds and retain moisture in the soil. Can also deter slugs and other pests.
CON – Can contain theobromine, a chemical toxic to dogs and other pets. May also be expensive and not readily available in all areas.
Sawdust or Wood Shavings
PRO: An inexpensive and effective mulch for suppressing weeds and retaining moisture. Can also improve soil structure over time as it decomposes.
CON: Can deplete nitrogen from the soil as they decompose, leading to nutrient deficiencies in plants. Can also be flammable and pose a fire hazard in dry conditions.
Inorganic Mulches
Gravel or Rocks
PRO – A long-lasting and attractive option that can be used to create a decorative and low-maintenance landscape. Ideal for arid climates where water conservation is important.
CON – Can be difficult to remove or change once in place. May also heat up and contribute to increased temperatures around plants, leading to potential plant stress or damage. Rocks must be kept away from trunks as they can abrade surface areas of bark.
Rubber or Recycled Tires
PRO – Provides long-lasting and durable coverage. Comes in a variety of colors and sizes.
CON – May release harmful chemicals over time and not decompose or contribute to soil health like organic mulches. Can also be visually unappealing in some landscapes. Beware of metal remaining in some rubber mulch recycled from tires.
Sand or Pebbles
PRO – Ideal for use in areas with high foot traffic or where drainage is a concern. Can also provide a decorative element to the landscape.
CON – Can be difficult to remove or change once in place. May also not decompose and contribute to soil health like organic mulches.
Landscape Fabric or Geotextile Membrane
PRO -Provides effective weed suppression and moisture retention, while also allowing water and nutrients to pass through to the soil. Can be used in combination with other mulches for added benefits.
CON – Can be expensive and not visually appealing. May also prevent some beneficial insects or organisms from accessing the soil.
Mulch, Compost and Fertilizer
Can compost be used for mulch? Do you need fertilizer if you use mulch – or is it compost you’re thinking makes good mulch? The terms can get confusing, so here is a summary for reference before you plan the next steps of caring for your young trees.
Mulch is a layer of material applied to the surface of the soil around plants or trees, typically for the purpose of conserving moisture, suppressing weed growth, regulating soil temperature and improving soil health. Mulch can be made from a variety of materials, including organic materials such as leaves, wood chips and straw, as well as inorganic materials such as plastic or rubber. Mulching is a common practice in landscaping and gardening and can provide numerous benefits to plants and soil when applied correctly.
Organic mulch supplies some nutrients to the soil as it decomposes, but young trees likely need additional nutrients to encourage root growth and overall health.
Compost is a type of organic matter that has been decomposed and transformed into a nutrient-rich soil amendment. It is created by combining organic materials such as leaves, grass clippings, food scraps (not meat) and other plant material in a pile or bin and allowing them to break down over time through the process of aerobic decomposition. A note of caution – when compost is going through the active stage of decomposition it is considered “hot” and can damage plants.
Compost can also be purchased commercially to be used as a soil additive or organic fertilizer. Quantities from single bags to truckloads are easily available. For those looking to cover a large area, many landscape companies will offer a ready-made solution of part soil, part compost so it’s ready to use as soon as the truck departs.
Compost is often used as a natural fertilizer in gardening and farming and is considered an environmentally friendly alternative to chemical fertilizers.
Fertilizers are used to supplement the nutrients in soil that may be deficient or depleted, as well as to enhance the growth and productivity of plants. They contain a combination of macronutrients, including nitrogen (N), phosphorus (P), and potassium (K), as well as micronutrients such as calcium, magnesium, and sulfur. For a more detailed information on ingredients and best practices, you can read our blog “The Scoop on Fertilizers.”
The type of fertilizer that should be used for young trees depends on a variety of factors, including the species of tree, the soil conditions and the age and size of the tree. Look for products that are high in phosphorus, which supports root development, and low in nitrogen, which can promote excessive leaf growth at the expense of root development. A balanced fertilizer with an N-P-K ratio of 10-10-10 or 12-12-12 may be appropriate for young trees but be sure to read the label and follow the manufacturer’s recommendations for application rates and timing.
Best Practices – the Do’s and Don’ts of Mulching
- Do use organic mulch, preferably shredded bark or wood chips, for mulching your young tree.
- Do mulch to within three inches of the trunk.
- Do spread the mulch out to be 2 to 4 inches deep.
- Do take the mulch out to the dripline – the end of the branches – of the tree.
- Do renew mulch yearly.
- Do not pile up against the trunk of the tree, creating an undesirable moisture trap and pest haven against the bark, often referred to as a tree volcano.
- Do not exceed four inches of mulch creating an unnecessary expense.
Note: Larger, more mature trees do not require mulching, but it still looks nice
Overall, mulching young trees using organic mulch and best practices gives you an increased likelihood of success. Proper mulching, watering, nutrients and pruning all add up to watching your new tree grow to its full potential. Imagine the 4-foot twig with a few leaves growing to shade the house on warm summer days!
At Miller’s Tree Service, we love watching the progress of young trees growing in the landscapes we service each year. At a certain point, they are added to our trimming list, assuring proper branching and air movement for tree health. If you need help with your new or old trees, or even have one that needs to be moved, we can help. Call to schedule a free consultation with one of our arborists – they love talking about trees! Contact us online here or call 850.894.TREE (8733) – we are invested in helping our neighbors keep their trees and landscape looking their best.