Mulching Trees and Shrubs
We know that mulch gives our gardens and outdoor space a natural, well-groomed finish; but did you know that it also delivers real benefits to the growth and long-term health of trees and shrubs?
In their natural habitat, trees benefit from an accumulation of organic matter found on the forest floor – that’s the twigs, leaves, branches, and other debris we’ve all walked through! But in our gardens, trees are faced with much harsher conditions, as well as some stiff competition from nearby weeds and grass.
One of the best things we can do to help reinstate the natural, nutrient-rich conditions of a tree’s native environment, is to mulch. Organic mulches such as a bark and wood chip not only protect tree roots and boost growth, but improve the long-term health of trees significantly.
So, what are the benefits?
Mulch provides a layer of insulation, protecting the soil and tree roots from severe weather fluctuations throughout the year.
Mulch prevents sunlight from fully penetrating, and drying out the soil. It will also significantly reduce evaporation from the soil surface.
As bark and wood chip naturally decompose, they release a range of nutrients and organic matter that enrich the soil and enhance its fertility.
Mulch prevents competition from other planted materials, allowing tree roots to receive their fair share of air, water and nutrients.
A ring of mulch protects trees from the injuries and damage that can be caused by lawn equipment, such as mowers and strimmers.
Start by determining the area you’re going mulch - it’s best to mulch right out to the tree’s drip line, that’s the outside edge where the longest branches reach. If this is not possible, a minimum 3 foot circle around the base is recommended. To keep yourself right, you may wish to mark this area
Remove all grass and weeds from the mulching area. You can do this yourself by digging up the grass using a spade, or applying grass killer – this can take around 2-3 weeks to kill the grass completely, but will allow you to retain more of the existing soil.
Once the area is clear of all planted materials, you can begin applying mulch outwards from the base of the trunk to the drip line, mulching to a depth of 2-4" (50-100mm). We’d recommend using a medium-coarse mulch, such as Decorative Mulch or Pure Pine Nuggets. Alternatively, you could use wood chip.
Finally, pull all mulch back from the base of the trunk by about 3-6”, so that the base is exposed. You are effectively creating a ‘doughnut’ ring shape around the base of the tree.
Don’t pile mulch around the base or create a “mulch volcano” – this puts the trunk under great stress, deprives the roots of air and water, and creates an ideal breeding ground for pests and disease.
Check the depth of your mulch every so often to ensure you're maintaining its full benefits. Depending on your mulch, when to replenish will vary. For medium-coarse mulches, such as Decorative Mulch or Pure Pine Nuggets, we'd recommend replenishing every 2-3 years.
If you have chosen an organic material, such as bark or wood chip, don't worry about removing the existing mulch - these materials naturally decompose and will release a range of nutrients and organic matter to enrich the soil below. Simply replenish your mulch to its original depth, and watch your trees and shrubs continue to flourish!