Mulching Your Garden: The best thing you can do right now

Gary Jones

Thu August 27, 2015 7:26pm

If you only have time to do one thing in your garden this month, what should it be? That’s an easy one: mulch. Sure, it would have been better if you’d done it mid-July, but it’s not too late to reap the benefits of a thick layer of organic or non-organic material.
What’s the purpose of mulching? Most gardeners do it for two primary reasons but there are multiple benefits. First, mulching conserves water by reducing evaporation. Second, it really cuts down on the number of weeds that sprout.
But there are other benefits as well. A thick layer of mulch keeps soil more evenly moist, which is important as nutrients are available to plants as soluble in water. A plant may get enough water to survive, but if it’s sporadic or uneven, it’s likely to be unhealthy and susceptible to disease and insect damage.
Many plants are just fine baking in the sun, but would prefer that their root zone be shaded. The hottest weeks in Southern California are during late August, September and into October. These are the months when plants are under the most stress — from both heat and drought.
Mulching reduces these stressors and helps plants get the nutrients they need.
Another benefit is aesthetic. A uniform soil cover just looks good. It brings together a garden’s appearance and provides a nice consistent backdrop to plants of all kinds.
Here are the three best mulches for home gardens:
Bark — Chipped or shredded bark is the most commonly-used mulch. It comes in small nuggets or large. The larger bark chips or nuggets will take longer to break down or compost and, therefore, last longer. But they can be hard to walk on. Smaller chips are often called walk-on bark. Barks of all kinds have a nice, rich organic look.
Gravel — This is a classic mulch or lawn replacement in Mediterranean climates such as the south of France and Italy. It seems, however, that larger rock has become a popular mulch in Southern California over the last year but can look rather coarse. Gravel is more refined and restful looking and much easier to walk on. However, both gravel and rock heat up a bit more than bark.
Leaves — Native oak leaves especially make a wonderful mulch, but any thick leathery leaf will do. Oak leaves don’t compost too quickly, yet they lay down flat and are easy to walk on. They have a nice uniform appearance.
Be sure you don’t fall into the trap of using fresh sawdust as mulch. It will compost very quickly, using a lot of nitrogen to do so. Your plants will be starved of nitrogen as a result.
Gary Jones is chief horticulturist at Armstrong Garden Centers. Email him your drought and gardening questions to