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Mulch "a trees best friend"

Updated: Nov 15, 2021


Mulching is one of the best things you can do to help your trees and plants thrive. This simple trick can help reduce water loss in your soil, reduce weed growth and add great cosmetic value to your garden and outdoor area. To top it all off it is great for your tree's health.

So what is mulching?

Mulching is the covering of the soil in a layer of organic or inorganic material.

A great example of newly planted trees with a large mulch area. Note it also has an irrigation system for watering.

What are the benefits of mulching?

There are lots of benefits to mulching but the two main benefits are:

  • Water retention in the soil - Organic mulch and some inorganic mulch reduce the water loss from the soil from evaporation, meaning there is more water for your trees and plant to use in the process of photosynthesis and respiration (growing). Plus more water is retained in the soil means you have to water your tree and plants less, saving you water and money.

  • Weed suppression - The mulch layer will reduce the light getting to bare soil and reduce weed that germination rates, this is not to say it will stop all weeds but it will decrease the number of weeds that will grow saving you time weeding. With less weed that also means less competition for your trees and plants for water and nutrients.

But mulching is not limited to just these two benefits it also:

  • Helps to regulate the soil temperature - This means that the soil is cooler in summer, letting the roots work more effectively in the heat. In winter the soil will warm quicker meaning the roots will start their spring growth sooner.

  • Organic mulch will create healthier soil over time - The breakdown of organic matter in the soil creates a humus layer which provides a habitat for earthworms that break up compacted soil and put more air into the soil (which roots need). The humus that is created is also used by beneficial fungi in the soil that help the roots work more effectively and release nutrients.

  • Help reduce soil compactions - As stated above, organic mulch helps break up compacted soil but the presence of mulch around a tree or plants actually reduces the likelihood of people and vehicles walking or driving over the root and soil area and which causes soil compaction. Find out more on soil compaction and how it’s bad for tree your tree at “Common mistakes made when caring for mature trees”

  • Decorative for the landscape - Mulching under a tree can also help define a landscape tree or a garden bed, adding a real depth and formal look to a garden.

Pro and cons of organic and inorganic

So what is the difference between organic and inorganic mulch then? Well, organic mulch is made from something that was living like fallen leaves, woodchips, and even newspaper or cards. Inorganic mulch is made of non-living things like river stones, shells, plastic weed barriers. Both have their pros and cons.

Depending on what you want to achieve with your mulch will depend on what type you choose. We nearly always recommend organic mulch such as wood chip or leaves. Organic mulch is by far the better option for our trees and plants for their health and well being because they mimic the natural woodland habitat and soil. Find out leaf mulching and how to do it at “Lockdown landscapes part 1: Leaf mulching".

How to mulch

In our exclamation of how to mulch we are going to be using organic wood chip mulch, we love this mulch as it is easy to get hold of from your local landscaping yard, cheap and great for the trees.

  1. Remove any large weeds and if you wish to, spray weeds, however, we don't recommend this because there is a strong likelihood that the wind will carry the weed spray onto your trees and plant.

  2. It’s best to apply when the soil is moist, like late winter and spring. If you haven't had any rainfall in the past couple of days, water the area well to allow that moisture to be trapped in the soil.

  3. If you're mulching for the first time add a layer of cardboard/newspaper to cover the ground you intend to mulch. This really helps with weed suppression and adds even more organic matter to the soil. But don't forget to remove the plastic tape from the boxes.

  4. Apply mulch to as large an area as possible, just passing the tree's drip line is best (where the longest horizontal branches finish). Make sure the mulch is at an even depth of around 5cm to 10cm, too much mulch can have a negative effect.

Things to remember when mulching

  • Don't place mulch against the stem of a tree or plant, make sure that there is a gap. If you pile mulch against the stem the heat of decomposing can burn the bark and cause rot and decay in the stem. Your mulch should NOT look like a volcano on the stem of the tree or plant.

  • Remember to top up your mulch every year or so as it decomposes, keeping that 5cm to 10 cm depth maintained.

  • You can add a rise or lip around the edge of your mulch layer to help reduce water runoff when watering. This is useful for young trees.

  • Let fresh wood chips sit and mature for a short time 1 to 2 months. This stops any chance of the french mulch drawing nutrients from the top of the soil, which it can when it is fresh.

  • It’s never too early or late to much your trees and plants, though starting young is best but mulching a mature tree properly will allow it to thrive for longer.

So what are you waiting for, get out there and mulch some trees! That little bit of effort will pay you back with less watering, less weeding and healthier trees. Remember investment in your trees will both benefit your property value and the future of our planet.

Oak tree, Torre Abbey Meadows, UK

Thought to be more than 450 years old, this venerable oak, standing along in the middle of the meadow, is now partly protected by a fence to discourage people walking over the roots, and surrounded by a mulch layer.

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