I Know This Mulch is True

Weed pressure, maintaining soil moisture, and protecting plants are all problems we face in our gardens. A great tool to help you with these issues is mulch.

What is mulch?
Mulch is any material placed on the soil surface to provide protection and improve the soil. In contrast, soil amendments are any material mixed into the soil to improve it.

What does mulch do in the landscape?
Mulch has a variety of benefits in the landscape including:

  • Preserving soil moisture by reducing evaporation.
  • Improving water penetration and air movement.
  • Helping control soil temperature.
  • Protecting plants from freeze damage and frost-heave.
  • Increasing microorganisms in the soil to reduce soil compaction.
  • Suppressing weeds.
  • Controlling erosion.Adding to the overall landscape interest or aesthetic.

What types of mulch are there?
There are a variety of options to choose from depending on your landscaping needs/wants, the size of the area, cost of materials, and availability. Organic mulch is most often used for soil improvements. Some examples include wood chips*, bark, shredded grass or leaves, seed hulls, pine needles, etc. Inorganic mulch is most often used for water conservation or weed suppression. Some examples are pea gravel and small stones. Ideally, any stone used for mulch should be smaller than a ½ inch in diameter to provide the most benefits. Any larger stone will not function as well at weed suppression or water conservation, but it will possibly provide better landscape interest.

Can I use weed fabrics or barriers instead of mulch?
Weed barriers and fabrics are not recommended as mulch for the typical landscape. Plastic weed barriers do not allow for oxygen exchange and prevent water penetration. Weed fabrics may initially allow for exchange of both oxygen and water, but they will eventually clog and create the same issues. Both easily germinate weed seeds as well, so they aren’t recommended as a barrier for weeds either if that is your goal. A better choice is to apply a good layer of mulch to the area where you are having problems. A correctly applied mulch layer will be better for your landscape and not cause any waste of your time, money, and effort.

When should I mulch?
Mulch can be applied at any time, but winter is often a perfect time to mulch. There is often less you need to do in your landscape, and you’ll be able to get in-between and under plants much easier.

How should I mulch?
Apply most mulch to a depth of 3-4 inches, including gravel. Mulch such as straw, grass, or dried leaves should be applied to a depth of 4-6 inches. A couple of tips:

  • Do not mulch too deep! Deep mulch can weaken plants and prevent oxygen and water exchange with the soil.
  • Do not mound mulch into “mulch volcanos” or “mulch mountains” around trees since this can decay the bark and interfere with the trunk.
  • Keep the mulch about 3 inches from the trunks of trees.
  • Do not lay weed fabric, newspaper, cardboard, etc. under your mulch area. Mulch applied to the correct depth does not require anything under it.

Is there anything else I should consider with mulch?
Keep in mind that every mulch has pros and cons. While gravel mulch is good at weed suppression and keeping more heat in the soil, it can also heat up buildings, utilities, or cause plants to grow too early in spring. Wood mulch has long lasting attractiveness, but you may need to add more nitrogen fertilizer to the soil as it decomposes. Grass clippings are a fast decomposer that’s perfect for vegetable gardens, but they need to be applied in thin layers and allowed to dry between applications to prevent mold growth.

For an extensive list of the pros and cons of various mulches, we recommend reading CSU Extension’s “Mulches for Home Grounds 7.214”.

Whatever you choose, Bailey Tree is here to help you keep your plants in top shape. Have our ISA certified arborists use their extensive education and experience to advise you on your tree needs. From trimming to fertilizing to watering, start your free estimate today!

*Bailey Tree does not offer mulching services.