Topping off a Perfect Landscape
Mulch conserves moisture and prevents weeds.
Cypress mulch should be avoided, since it uses valuable cypress trees. Use can use hardwood or Pine bark chips for mulch. The larger the chips, the slower they decompose. Pine straw is the least expensive, but it makes a very pretty cover.
If you use fresh bark or hardwood chips, you might also want to add some additional nitrogen to the mulch at first to counter the organic breakdown of the chips. New chips use up a small amount of nitrogen in the process of rotting down.
Spread mulch no deeper than 3 inches. Thicker mulch will harm nearby trees. Really thick mulch will encourage the trees to send feeder roots into the mulch instead of the soil, because they need oxygen, and can’t breathe if they are buried too deeply. A recent trend has been to rake mulch up into a tall cone around the trunks of trees. Why do people do things like this? Keep mulch at least 2 inches away from any tree trunk. There are lots of bugs living in mulch and you don’t want to invite them up into the tree.
If you are worried about weeds growing in mulched areas, then keep the areas weeded. Don’t use weed fabric or black plastic “mulch”. Black plastic blocks water and air to the roots. Soil and particulates drift on to the top of weed fabric. That is all any weed needs to germinate and grow right through the top of the fabric. Then, when you try to pull the weed, you end up pulling the fabric with it. It’s a mess! With a nice layer of mulch and a little vigilance, there should be no need for weed-blocking fabric. Healthy trees will eventually begin producing leaf litter that will create its own mulch each year.
Don’t rake away the leaf litter under trees! Keep it. It is free mulch and helps harbor good nutrients. You might even want to pick up full leaf bags deposited at the curb by your neighbors to bring back to your trees and plant beds. Just keep the depth to no more than 3 inches.
The latest trend in mulch is to add recycled rubber or inorganic pellets to plant beds. The sales pitch says it will provide a maintenance-free, weed-free landscape. Inorganic, recycled materials don’t break down and don’t provide nutrients to the soil, which is one of the amazing benefits of organic compost. There are no mycorrhizae produced because the circle of life doesn’t turn for inorganic material. A plastic doll is not the same thing as a real girl, and recycled tires are not the same thing as pine bark nuggets. The recycled materials don’t breathe and might heat with exposure to sunlight rather than cooling the roots of the plants. The artificial coloring added to make the pellets look natural might also break down under ultraviolet rays and fade. Proceed with caution when using inorganic material pretending to be natural.
Topping off a plant bed mixed with the right amount of fertilizer, lime, organic matter, grit, and hope should be a three-inch protective mulch layer. Mulch keeps the roots cool, holds in soil moisture, and shuts out sunlight to weed seeds to discourage them from sprouting.