The Truth About Mulch (It's More Important Than You Think)

I used to think mulch was purely cosmetic. You put down the dark stuff, your beds looked tidy, homeowner mission accomplished. Then I learned what mulch actually does and I started taking it a lot more seriously.

What Mulch Actually Does

Retains soil moisture (less watering). Regulates soil temperature. Suppresses weeds by blocking light to weed seeds. Breaks down over time and adds organic matter to your soil. Prevents erosion. Makes beds look clean. That’s a lot of work for some wood chips.

How Much to Apply

Two to three inches is the target. Less than two inches and it doesn’t suppress weeds effectively. More than three inches and you risk smothering plant roots and creating wet conditions that invite disease.

The Volcano Mulch Problem

Drive through any suburb and you will see trees with mulch piled up against the trunk like a little volcano. This is wrong and slowly kills trees. Mulch against bark traps moisture, invites rot and pests, and can girdle a tree over years. Keep mulch a few inches away from any trunk or stem. Flat, not volcanic.

Which Type to Use

Shredded hardwood bark is the workhorse. It looks good, lasts a reasonable time, and breaks down into decent organic matter. Pine straw works well around acid-loving plants. Rubber mulch lasts forever but doesn’t add anything to the soil and I’m not a fan. Cedar smells great and has mild insect-repelling properties.

Apply it in spring after the soil has warmed. Refresh annually.