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Mulch

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There are a number of advantages to mulching the soil around trees and shrubs.
Photo: Jardin botanique de Montréal (Lise Servant)  
Taxus x media 'Densi-Gem'

There are a number of advantages to mulching the soil around trees and shrubs. For best results, it is important to choose good-quality organic mulch and to follow a few simple rules.

Why mulch?

  • it conserves soil moisture;
  • it controls weeds;
  • it moderates variations in soil temperature;
  • it adds nutrients and organic matter as it decomposes (if you use organic mulch);
  • it prevents erosion and prevents a crust from forming on the soil surface;
  • it protects the trunk from lawnmower and edge trimmer damage;
  • it protects the roots when there is not enough snow cover;
  • it improves the appearance of planting sites;
  • it provides shelter for helpful organisms in the garden and stimulates the soil's biological life;

Choosing mulch

  • It is best to use organic mulch. Examples are : ramial chipped wood, shredded bark (such as cedar or hemlock mulch), wood chips, forest mulch, shredded dead leaves, buckwheat hulls, etc.;
  • Avoid using decorative stones and geotextile cloth and membranes, which interfere with gas exchanges between the soil and air;
  • Make sure that the mulch doesn’t contain any toxin;
  • Note that very light mulches can be scattered by the wind in exposed areas.

Applying mulch

  • Apply a layer of mulch 8 to 15 cm thick before it settles;
  • Be careful not to stir the mulch into the soil;
  • To prevent decay, keep the mulch 10 to 15 cm away from the collar on the trunk;
  • Water the soil before mulching, then water the mulch to keep it in place.

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