Commercial Mulching Programs

Why mulch is the highest return item in a bed

Mulch does four jobs at once, which is unusual for anything in a landscape budget.

It blocks light, so weed seed cannot germinate. It slows evaporation, so beds hold water longer between cycles. It keeps soil temperature down, which matters a great deal against reflected heat off pavement. And as it breaks down it adds organic matter to soil that is almost always short of it.

The fourth job is the one people forget, and it is why replacing mulch entirely is usually wrong. The lower, partly decomposed layer is doing the soil work. Top up over it rather than stripping it out.

the depth at which mulch actually suppresses weeds

3 inthe depth at which mulch actually suppresses weeds

typical top up frequency per year on a commercial bed

2xtypical top up frequency per year on a commercial bed

jobs it does at once: weeds, water, heat, and soil

4jobs it does at once: weeds, water, heat, and soil

Choosing the material

Most commercial properties use shredded bark or wood chip, and the choice between them is mostly about wind and appearance.

Fine material looks refined and blows in a Santa Ana. Coarse material stays put and reads as less finished, which is fine at a perimeter and less fine at a leasing office entrance.

Rock is not mulch. It suppresses weeds, it does not break down, and it stores and radiates heat, which stresses planting in a climate that is already hot. It has a place in narrow strips and drainage swales, and it is a poor choice around plants.

Rubber mulch has the same heat problem plus a disposal one. Where a property has it, replacing it with organic material usually improves plant health noticeably.

Applying it so it works

Most of the value in mulch is lost in the application rather than the material.

Weed first, properly, because mulch over established weeds suppresses very little. Pull, do not cut, and get the roots out.

Then depth. Three inches across the bed, not two inches with a thick band along the visible edge, which is common and fools nobody once the interior fills with weeds.

Then the stems. Mulch against a trunk holds moisture where the plant needs air and causes rot at exactly the point that kills a plant. Pull it back a few inches from everything woody.

1. Weed the bed thoroughly, removing roots rather than tops
2. Cultivate the surface lightly so mulch beds down rather than sitting on a crust
3. Apply to three inches across the whole bed
4. Pull mulch back from every trunk and stem
5. Check the depth against adjacent hard surfaces so it does not wash out