Mulching for a better garden.
Mulching is one of gardening’s oldest techniques. We’ll be talking about bark mulch or other organic mulches that improve the soil along with other added benefits. Many materials in mulch can also be used as soil amendments - when using bark you’ll see they incorporate into the soil to improve its texture and structure. Mulch is applied in a fairly thick layer on top of the soil, and although it performs many of the functions of an amendment, mulch has a number of other positive effects.
Mulches serve to keep the wind and sun from baking the soil and causing it to form a crust, keeping the soil cool. It helps with weed control and water conservation – both problems for home gardeners.
Bark Mulch is one of the most popular mulches around, because it looks so great once you put it down. It is also an excellent choice when it comes to water preservation, since it provides a solid barrier against moisture evaporation. The one disadvantage of this mulch is its size. Most bark mulch comes in large chips, which decompose slowly. If you can find bark that's been shredded, go that route. Shredded bark will not only trap moisture in your flower beds better than large chips, but since it decomposes quicker, it more readily adds nutrients to the soil as well. Whether you choose bark mulch, or another variety, it's important that you take into consideration the prevalence of wood boring pests in your area before you purchase. Termites, for example, prefer to munch on dead wood, and wood based mulch is a favorite feeding ground. If you live in an area where termites are commonplace, it's probably a good idea to talk to a pest control contractor or landscaping contractor before making your purchase. It can be the difference between a maintenance free landscape, and one that causes scores of headaches and larger problems down the road. If termites are not a problem in your area, wood mulch is about the best investment you can make when it comes to landscaping. You'll be getting one of the best looking, and performing, mulches on the market. Or you could consider Cedar Mulch.
Cedar Mulch is the elite of the mulch. Because cedar has natural oils in the wood that repel insects, it's the perfect choice for wood mulch, especially in areas where termites are common. Cedar mulch is going to be a little more costly initially, but it's well worth the extra expense when you consider its pest repellant properties.
Cedar mulch comes from the bark of the cedar tree, an evergreen that grows abundantly in U.S. Department of Agriculture plant hardiness zones 7 through 9. In mulch form, cedar is either shredded or chipped. Shredded cedar mulch creates an airy, light layer over soil. Its fine texture works best with smaller plants such as annuals and perennials. Cedar chip mulch is best used in beds that contain larger plants, bushes and trees due to its heavy, denser nature. It is one of the more expensive types of mulch, so when you purchase cedar mulch, make sure the content is actually cedar. What is often labeled “cedar mulch” is in fact mulch made from other types of wood and then dyed. So read the labels carefully.
Unlike many other types of organic mulch, cedar mulch decomposes slowly, taking years to break down, so it needs to be replenished less frequently. The resins in cedar mulch emit a pleasant scent. Anyone who has a cedar closet or dresser drawers lined with cedar knows that cedar has pesticide properties and may keep certain types of insects away from plants.
Fresh cedar mulch uses the soil’s nitrogen as it decomposes, making that nitrogen unavailable for the plants it is protecting. This nitrogen issue affects only the soil in direct contact with the mulch, and will not affect the plants as long as the mulch is not mixed into the soil. To avoid possible nitrogen depletion, periodically fertilize plants mulched with cedar.
Spreading a protective layer of some sort of organic mulch over the bare soil in planting beds and under trees in residential yards is very important. Unfortunately, mulching trees often becomes too much of a good thing, as uninformed homeowners and landscape crews pile wood chips or shredded bark too thickly over the soil and too high up against tree trunks. Rather than protect the tree, this “volcano” mulching can kill it. Because many landscaping companies fail to train their workers on how to properly spread mulch under trees, it is important for homeowners who hire them, (as well as those who do their own mulching in their yards), to be aware of the correct way to mulch trees and shrubs.
Never let mulch touch the trunk of the tree. Start the mulch layer on the ground about 4 to 6 inches out from the bottom of the trunk. The root flare, where the roots begin to enter the ground at the base of the trunk, should be visible after the mulch is spread.
Never let the layer of mulch under a tree become deeper than 3 or 4 inches.
Spread a wide layer of mulch to cover the spreading root system. Remember that tree roots typically spread well beyond the reach of a tree’s branch canopy. So, extend the mulch layer as least as far as that.
Stone or gravel mulches do not benefit trees or soil.
For more details contact your local Extension Office for tips and additional information on MULCH or other gardening issues.
Written by Gloria Polakof, PhD
