Mulch On a Mission

Available in organic and inorganic forms, mulch comes in many shapes and sizes. Choosing the right one depends on where you plan to use it.

In the world of gardening, there are many different types of mulch for your landscape. Deciding which to choose depends on where you plan to use it. But first it helps to know mulch’s mission.

Mulch provides essential carbon and energy for all macro and micro organisms. These organisms breakdown the smaller carbon constituents and other organic matter into molecules that plant roots can absorb. Mulch also encourages water to permeate the soil, while diminishing the potential for evaporation.

Ever the multitasker, mulch also reduces soil temperature to facilitate root growth and it discourages weed germination and growth.

Here is a simple breakdown of the various types of mulches, along with their pros and cons so you can make the most of mulch.


Products like woodchips, pine bark, pecan shell, pine needles, straw and live oak leaves provide nutrients to the soil.

Hardwood chips

  • Pros
    • Composed primarily of cellulose (carbon); decomposes easily.
    • Available locally in many forms.
  • Cons
    • Decomposes quickly.
    • Aesthetics depend on the type of chipper used to produce it (drum, hammer, or disk).
    • Floats away in heavy rainfall.


Pine bark chips or chunks

  • Pros
    • Composed primarily of lignin so it doesn’t decompose easily; not palatable to most insects.
    • Aromatic and pleasing to the senses.
  • Cons
    • Occasionally difficult to find.
    • Floats away in heavy rainfall.
    • Larger chunks can be habitat for insects.

pine tree bark mulch

Cedar wood (shredded)

  • Pros
    • Decomposes slowly due to decay-resistant chemicals in the wood.
    • Does not float away during heavy rainfall.
  • Cons
    • Often forms an impenetrable matte that limits air and water infiltration.
    • Aesthetics are in the eye of the beholder.

spreading shredded mulch

Live oak leaves

  • Pros
    • They’re everywhere.
    • Decompose slowly.
    • Permit air and water infiltration.
    • May be stacked 4-6 inches.
  • Cons
    • Decomposes slowly.
    • May scatter easily.
    • Aesthetics are in the eye of the beholder.

oak leaves close-up


Products such as decomposed and rolled granite types are typically incorporated into the landscape to facilitate drainage.

Decomposed granite/pea gravel

  • Pros
    • Never decomposes.
    • Aesthetics are in the eye of the beholder.
  • Cons
    • No nutrient benefits.
    • Absorbs heat.
    • Clogs drains and sewers.

Mulch is essential for healthy soil and proper water management. Maintain between one and two inches of it on your garden beds.

Picture of Mark Peterson
Mark Peterson
Mark A. Peterson was a conservation project coordinator for San Antonio Water System before retiring. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you're likely to find him hiking San Antonio's wilderness parks or expounding on the virtues of geography and history to his friends.
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