Why Mulching Around Trees Helps Soil and Root Health

If you have trees in your Bayside garden, whether it is a established gum in a leafy Brighton backyard or a young ornamental in a Sandringham courtyard, mulch is one of the simplest and most effective things you can do to keep them healthy. A layer of organic mulch spread correctly around the base of a tree works quietly in the background, protecting roots, feeding the soil, and helping your tree handle the stresses of Melbourne's changing seasons. In this guide, we explain why mulching matters and how to do it properly in 2026.

What Mulch Does for Tree Roots

Most of a tree's absorbing roots sit in the top 30 centimetres of soil, and many extend well beyond the canopy edge. These fine roots are the working parts of the tree. They take up water, oxygen, and nutrients, and they are easily damaged by compaction, lawn mowers, and drying out. A good mulch layer shields this root zone from these pressures and creates a more stable environment in which roots can grow and function.

Moderating Soil Temperature

Bayside summers regularly bring hot, dry spells with temperatures well https://baysidetreeremoval.com.au above 30 degrees, and exposed soil can heat up quickly. Mulch acts as an insulating blanket, keeping the soil cooler in summer and slightly warmer during cold snaps. Stable soil temperatures reduce stress on roots and help prevent the sun scald and heat damage that can weaken young trees.

Conserving Moisture

Mulch slows evaporation from the soil surface, meaning water applied during watering or rain stays available to roots for longer. This is especially valuable for newly planted trees, which need consistent moisture while their root systems establish. A 75 to 100 millimetre layer of mulch can significantly reduce how often you need to water, which also helps with water conservation.

Suppressing Weeds and Grass

Grass and weeds growing right up against a tree trunk compete with the tree for water and nutrients. A mulched zone keeps this competition down without the need for herbicides, which is important for trees whose roots are sensitive to chemical disturbance. It also removes the risk of damaging the trunk with a whipper snipper or mower.

Building Healthy Soil Over Time

As organic mulch slowly breaks down, it adds organic matter to the soil. This improves soil structure, helps clay soils drain better, helps sandy soils hold more water, and feeds the fungi and microorganisms that form beneficial partnerships with tree roots. Over several years, a mulched tree zone often develops richer, darker, more crumbly soil than the surrounding lawn.

How to Mulch Around Trees Correctly

Getting the technique right matters as much as the decision to mulch. Done poorly, mulch can cause more harm than good. Here are the key guidelines to follow:

1. Spread mulch in a wide ring, ideally extending to the drip line of the canopy, or at least 1 to 1.5 metres from the trunk for smaller trees.
2. Keep mulch 10 to 15 centimetres away from the trunk. Piling mulch against the bark traps moisture, invites rot and pests, and can encourage root collar problems.
3. Apply a layer of 75 to 100 millimetres of coarse organic mulch such as wood chips, bark, or leaf mulch. Avoid stacking it deeper, as this can suffocate roots.
4. Use the right material. Arborist wood chips, pine bark, and leaf litter are all good choices. Avoid fine, sour, or unaged materials that can become waterlogged or rob nitrogen from the soil.
5. Refresh the layer yearly or every two years as it breaks down, but do not let it build up over time.
6. Avoid volcano mulching, the common mistake of mounding mulch up around the trunk, which is one of the most damaging habits in home gardens.

Mulching Tips for Bayside Gardens

Bayside's coastal soils can be sandy and free-draining, particularly in areas close to the bay, while some inland pockets have heavier clay. Mulch helps in both cases, but in sandy soils it is especially useful for retaining water, while in clay it supports better drainage and structure. Check your local council guidelines before removing any street trees or working near protected vegetation, as tree protection rules in Bayside can apply. If you are unsure how much mulch to use or whether your trees show signs of stress, a qualified local arborist can assess the root zone and recommend an appropriate plan.

With a little care, a well-mulched tree zone rewards you with healthier roots, stronger growth, and a garden that handles dry summers and wet winters with far less effort. Start this season by clearing the grass from around your trees, spreading a proper layer of mulch, and keeping it pulled back from the trunk.

Bayside Tree Removal

Shop 6/1 Taylor St, Moorabbin VIC 3189

(03) 8400 0915