Skip to Content

Mulching and Soil Improvement

In shrub and flower beds, bare soil dries out more quickly and is an open invitation to weeds. Adding organic matter and a layer of mulch will help the soil retain moisture, restrict weed growth and return nutrients to the soil as it decomposes.

  1. Cultivate the soil in your shrub and flower beds regularly and incorporate organic matter like compost. This improves the condition of the soil and helps to retain moisture.
  2. Spread a 2″ to 4″ layer of mulch in shrub and flower beds and around trees in the early spring and fall.
  3. Keep mulch away from the base of shrubs and trees to prevent decay and disease.
  4. Choose a mulch based on your preference and soil needs:
  5. landscaping-mulch-soil

  • Bark – Long-lasting, available ground, shredded or in chips. Fir, pine, hemlock or redwood are long-lasting and attractive. Fine textured sawdust and wood shavings will need a nitrogen supplement to aid in decomposition (if not shown on the package label, add it to the soil before laying the mulch down).
  • Straw – Short-lived, inexpensive and virtually free of weed seeds.
  • Aged or composted animal manures – Effective for about one year. Make sure it is aged or composted as fresh manure can burn plant roots as well as contain weed seeds.
  • Agricultural by-products – Availability varies by region and may include mushroom compost, ground corncobs, and apple or grape pomace. Check your local garden center to see what is available.
  • Duff – The natural mulch from fallen leaves, twigs, and other small dry material. If leaves or twigs are large, chop them into smaller pieces with a sharp shovel. Thin leaves can compact into a water repelling mat if they are not mixed with some coarser material. (Do not use dried weeds as the seeds will still be viable.)
  • Grass clippings – Short-lived and easily mats; must be applied in thin layers and allowed to dry before adding more.
  • Inorganic mulches – May include rocks and plastic. Although they prevent erosion and minimize weed growth, they do not restore nutrients to the soil and plastic will prevent water percolation. For water conserving maintenance, organic mulches are a better choice.
William Lowe
Latest posts by William Lowe (see all)