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Mulching 101: How to Mulch Your Trees the Right Way

by Admin on
Arborist Tips Gardening Soil Amendment
Mulching is one of the simplest and most effective ways to care for your trees. When done correctly, it helps retain soil moisture, suppress weeds, and improve overall soil health. 

Too"mulch"of a good thing?

Too much mulch, or improper application, can cause serious issues like root rot, insect infestations, and poor hydration.

In this article, we’ll share expert mulching tips and best practices to ensure your trees thrive. Whether you’re prepping for winter or enhancing your garden year-round, these guidelines will help you avoid common mulching mistakes.

Not all mulch is created equal. Mulch includes any material used to cover soil, while wood chips are coarser and often made from freshly chipped trees. Wood chips work well for established trees but may not suit young plants or gardens needing finer textures.

  • Arborist mulch is local, high nitrogen mix of woody and plant debris derived from local tree service chipping
  • Leaf mold mulch is made through anoxic fungal decomposition
  • dyed black mulch is dyed with natural carbon but also may contain creosote or other concerning preservatives
  • dyed red mulch is coloured with iron oxide but also may contain creosote or other concerning preservatives
  • Detailed view of wood chippings in a pile

Avoid dyed mulches from garden supply stores. These often contain recycled wood from pallets or treated lumber, which can introduce harmful chemicals. The dyes can also leach into the soil, affecting plant health. Opt for organic, untreated mulch or composted wood chips for safer, more effective results.

Mulching in 3-Simple-Steps

Before adding mulch, inspect the area around your trees and plants.

  • Ensure the soil has adequate drainage to prevent water-logging.
  • Check for nearby plants that might be affected by the type of mulch or the mulching process. e.g. avoid acidifying the soil with a pine mulch and go with hardwood if your plants prefer a more neutral pH.

Organic mulches are ideal because they enhance soil health as they break down. Options include:

  • Composted Wood Chips or Leaf Mold: a composted mix that includes leaves, bark, and wood is highly effective and enhances soil quality
  • Fresh Wood Chips: Suitable for established trees and shrubs.
  • Other Organic and Green Mulches: Arborist mulch containing shredded leaves, branches, bark and twigs or other mulch mixes with pine needles or straw are unconventional looking but work as an organic fertilizer by infusing nitrogen back into the soil to enhance growth.

Avoid using inorganic materials like rocks or rubber mulch, as they do not provide the same soil-enhancing benefits.

Proper mulching means spreading mulch in a wide, donut-shaped ring that extends out to the tree’s dripline (the edge of the canopy).

Mulch should be no more than 2–4" inches (5–10 cm) deep and must be kept away from the trunk. The tree’s root flare should remain visible and uncovered.

Avoid “mulch volcanos” caused by piling mulch against the base of the tree, this technique traps moisture against the bark and can lead to decay and root problems.

 (Below) Improper vs. Proper Mulching TechniqueProper mulch technique - colour highres with text

  

Root collar area
(Left) Root Collar Area

Identification of the root collar (aka trunk or root flare) on a tree is critical.

Mulch should always be kept 4-8" away from the collar and not cover the base (trunk) flare - a critical site of oxygen exchange for the tree.

Mulching: 3 mistakes to avoid

  1. Over-Mulching: Using more than 4" inches (10 cm) of mulch  can suffocate the root collar and or lead to poor aeration in the soil.
  2. Improper Placement: Mulch that touches the main portion of the tree trunk or root flare can create a breeding ground for pests and fungi.
  3. Ignoring Existing Layers: Failing to rake or remove old mulch can result in compaction and reduced soil oxygen. Putting  down landscaping fabric on dry soil and piling mulch on top may exacerbate soils that have become hydrophobic because water runs off the fabric and is unable to penetrate the dry substrate.

By avoiding these pitfalls, you’ll ensure your trees get the full benefits of mulching without the downsides.

 

Why mulching matters for tree health

At Arbutus Tree Service, we recommend mulching as a key component of tree care. Whether you’re maintaining your landscape year-round or getting ready for winter, proper mulching can help your trees thrive in Vancouver’s unique climate.

If you have questions about mulching or tree care, our experts are here to help. Contact us today to schedule a consultation or learn more about our tree care services.

For more on this topic, check out Proper Mulch Technique (pdf guide) from Trees are Good.

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