January 2012 Articles

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Mulching is good landscape practice

Mulching is good landscape practice By LSU AgCenter Horticulturists Dan Gill, Kyle Huffstickler and Allen Owings
Mulching flowers, trees and shrubs is a great sustainable landscape practice when done correctly.
Organic mulch materials, such as pine straw, pine bark, compost and chopped leaves, improve soil fertility as they decompose. In addition, mulch buffers soil temperature, keeping soils several degrees warmer in winter and cooler in summer. It can help maintain soil moisture by reducing evaporation and minimize water needs for established plants.
Mulching can be done almost any time of the year. We normally recommend home gardeners apply mulch in spring and then add more in fall. In addition, it’s common to use mulch during the winter. Leaves and plant debris collected from yards in fall make good mulch material for many plants.
In order to maximize mulch benefits and minimize problems from mulching improperly, learn how to use mulch in the landscape and know how to apply it properly.
Layers of mulch around trees, shrubs and planted beds as well on bare ground provide many benefits. In areas that are difficult to mow, irrigate or otherwise maintain, mulch can replace turf or ground covers. Also consider placing mulch in shady areas where plants don’t grow well.
One of the major overlooked facts of mulching is how it inhibits germination and subsequent growth of weed seeds. A layer of mulch, primarily pine straw, will partially block sunlight penetration to the soil surface. Many weed seeds lie on top of the soil and require light to germinate. If mulch is present to block the light, seeds may never germinate.
Over time, many types of mulch improve soil aeration, structure and drainage. In areas with compacted soil and little desirable plant growth, continually mulching for a couple of years will gradually loosen the compacted soil. This will allow more drainage and aeration and will improve the area for plant growth in the future.
Applying mulch around trees and shrubs – but not against the trunk – eases maintenance and reduces the likelihood of damage from string trimmers. Unfortunately, “volcano mulching” – piling mulch in in a cone shape around the base of a tree or shrub – is now becoming common. This hinders oxygen exchange to roots, which causes plant stress and root rot.
Do not place mulch on top of a tree’s root ball or against the trunk. Mulch that’s deeper than about 3 inches on top of the root ball area of newly planted trees and shrubs can stress plants because it can intercept water meant for the roots. Remember to go outward rather than upward with mulch.
Finally, mulch gives planting beds a neat and uniform appearance, adding a contrast of color and texture that complements plantings. Most mulches fade in color over time, but they can and should be replenished to maintain their effectiveness and attractiveness.
Remember the many advantages of using mulch in your landscape. When properly applied, it goes a long way in improving performance of your ornamental plants and adds a nice, aesthetic improvement to your landscape.