As winter draws near, one important step to protect and support your soil and plants (native and non-native) is to mulch.  Mulch helps slow run-off, promotes water retention in the soil, and as it breaks down it provides a slow-release supply of nutrients.  It also protects roots in freezing weather.

Most of us are familiar with using wood chips as mulch.  They are available for free from many tree companies, but they come as a big load and you might want to share with a few neighbors. The source of the chips doesn’t matter, even eucalyptus is fine, as well as oak that died of SOD.  Smaller chips are vastly preferable to large.

However, a variety of different substances can perform as mulch. 

• Leaf litter – if your gardener blows your leaves, use them under shrubs and trees (keeping the trunk clear), but don’t disturb your mulch by allowing your gardener to blow it away.
• Compost – you don’t need to work it into the soil, the micro-organisms will do that for you. It is a great mulch for plants that have large nutrient needs (fruit trees).But compost can be expensive.
• Wood chips – wood chips are a great low-cost mulch, but smaller chips are preferable to larger ones that take much longer to decompose. Potentially flammable mulches must be kept >5’ away from the home.
• Rocks – particularly with low water or desert plants, and in the initial 0-5’ perimeter around your home, rocks or gravel are an excellent mulch – Any size are good, but decomposed granite and pea gravel are often used. Add a couple of larger rocks (2-3 lb or so) which provides a condensation surface and source of moisture. The larger rocks when placed on the South side of a plant dissipate the mid-day sun and prolong the evening’s warmth. This works well when placed near newly installed plants.

Keep some areas mulch free, ground nesting bees need access to the soil to reproduce.

NEVER use tire or other man-made materials as mulch, they contain many toxic chemicals.

Also do not use dyed mulch.  It’s trendy now, but it’s unnatural and has unintended consequences, for example, the black mulch rapidly heats up and dries the soil as it absorbs more of the sun’s energy.