Mulching is the most beneficial treatment that you can provide to your newly planted or established trees and shrubs. Mulching involves the application of a protective layer of material, such as organic matter or inorganic materials, around the base of trees. It feeds and protects their roots, )by providing necessary water and nutrients for trees to grow. Of course, roots are also anchors to keep trees and shrubs standing when exposed to natural environments.
Natural vs Urban mulching
A natural undisturbed forest environment provides trees with well aerated soil with no compaction or soil disturbances. A wide range of living organisms (virus, bacteria, fungus, or soil microorganism greatly contribute to the health and well-being of trees and shrubs. Tree roots in a natural forest are covered with organic material replenished by leaves, twigs, or wood – natural mulch.
Tree and shrubs growing in urban and disturbed areas where soil structure is significantly changed have a harder time surviving or thrive. Root development is usually limited due to poor soil quality, lack of nutrient replenishment and more exposure to constant soil fluctuations.
What are the benefits of mulch?
There are several benefits that mulch provides to trees and shrubs:
1. Soil Enrichment – One of the primary advantages of tree mulching is its role in soil enrichment. Organic mulches gradually decompose, releasing essential nutrients into the soil. This process enhances soil fertility, promoting healthier tree growth. The decomposition of mulch also improves soil structure, aiding in water retention and drainage.
2. Water Conservation -Mulching acts as a natural water conservation method. The layer of mulch helps retain soil moisture by reducing evaporation, especially in hot and arid climates. This is particularly beneficial for young or newly planted trees that require consistent moisture for establishment. The retention of water also reduces the frequency of irrigation, contributing to water conservation efforts.
3. Weed Suppression- Mulch serves as a natural barrier against weeds, inhibiting their growth and competition for resources with the tree. This is particularly important in urban and landscaped areas where weed control can be challenging. By preventing the growth of weeds, mulching reduces the need for herbicides, promoting a more eco-friendly and sustainable approach to landscaping.
4. Temperature Regulation – Mulch provides insulation for the soil, acting as a buffer against extreme temperatures. In hot weather, it helps keep the soil cool, preventing root damage caused by overheating. Conversely, during colder periods, mulch acts as an insulator, protecting tree roots from frost and freezing temperatures. This temperature regulation is crucial for maintaining optimal conditions for root development and overall tree health.
5. Erosion Prevention – In areas prone to soil erosion, tree mulching plays a vital role in preventing the loss of topsoil. The protective layer of mulch acts as a barrier, reducing the impact of rainfall and preventing soil erosion. This is particularly important on slopes or in areas with poor soil structure.
6. Damage Prevention – mulching protected roots and trunk from mechanical injuries from lawnmower and weed whackers
7. Improve soil microbial community – The soil microbial community plays a crucial role in nutrient cycling, maintenance of soil structure and its diversity is a sensitive indicator of soil quality
Types of Mulch
There are organic and inorganic mulches. Organic mulches are natural materials such as wood chips, straw, flax shives or bark. Inorganic mulches are inanimate materials like various types of plastic mulch, stone, lava rock, pulverized rubber and geotextile fabrics.
Both of these mulches have positive and negative qualities. Organic mulches provide necessary nutrients to soil, improving the soil structure, but will need to be replenished. Inorganic mulches do not provide any nutrients to the soil or the soil structure, but they do not need to be replenished, saving on related costs.
Best Practices for Mulching
- Avoid Mulch Volcanoes – One common mistake in mulching is creating mulch volcanoes – piling mulch against the trunk of the tree. This can lead to moisture-related diseases, pest issues, and even the death of the tree. To avoid this, create a donut-shaped ring of mulch around the tree, leaving a gap near the trunk.
- Proper Mulch Depth – Maintaining the right depth of mulch is crucial. Too little mulch may not provide the desired benefits, while excessive mulch can lead to problems like root suffocation and excessive moisture retention. Aim for a depth of 4 to 6 inches, gradually tapering towards the outer edges of the mulch ring.
- Choose the Right Mulch – Selecting the appropriate type of mulch is essential for maximizing its benefits. Organic mulches are preferred for their nutrient contribution, but the choice may depend on factors such as local availability, cost, and aesthetic preferences. Avoid using mulches containing diseased plant material to prevent the spread of pathogens.
- Regular Inspection- Regularly inspect the mulch layer to ensure it remains effective. Top up mulch as needed to maintain the desired depth and remove any weeds that may penetrate the mulch. Periodic inspection allows for adjustments based on the changing needs of the tree and its environment.
Be Aware
- Some grass, straw or flax mulches may have chemical residues in them that can be detrimental to your tree
- Inorganic mulches like rubber or plastic can be negative to trees, soil and the overall environment
- Do not apply very fine sawdust as it can create a water-resistant layer on the soil
- Inorganic mulches such as lava rock, marble chips, gravel, or other hard, non-organic mulches could lead to soil compaction and do nothing to cool the soil or add organic matter.
- Dark-colored mulches absorb heat during the day and may sometimes injure the bark of the tree or shrub.
- Organic mulches on nutrient-poor soil can decompose in the first year, creating some nitrogen deficiency.
Proper mulching is the key to maintaining healthy trees and shrubs for all to enjoy. Using mulch to protect roots from human induced damages like compaction and construction, or environmental damages such as frost or flood is one way to ensure the health and vitality of your trees and shrubs.
How can we help?
Our professional and experienced Tree Expert and ISA Certified Arborist offers a full range of consulting and advisory services to help you keep your trees healthy. Hire Yard Whispers Tree Expert/Arborists or our parent company ATTS Group to inspecting your tree and recommending a solution that’ll meet its specific needs
