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Saturday, March 11, 2000

Not all mulches are equal

Organic types have economic benefits

 

Gardeners have applauded the use of mulches for years. Mulches help conserve water, reduce erosion, moderate soil temperatures and control weeds. They also can provide uniformity and a clean, finished look to a landscape. Finally, they can protect trees from weed trimmer and lawnmower damage. However, not all mulches are alike. The range of material available for mulching falls into two basic categories: organic and inorganic. Each has its advantages and disadvantages.
   Organic mulch
   A wide range of organic mulches are commercially available. These products have vastly improved since the early days of pine bark nuggets that floated away at the first hint of rain. A finer grade of pine bark mulch is now the industry standard to provide a rich, dark topping for flower beds.
   However, shredded mulches are also very popular because of their ability to intertwine and stay in place, even after heavy rains. The most common shredded form is cypress mulch, but eucalyptus mulch is also making its way into the marketplace. Many landfills, including the J.C. Elliott landfill in Corpus Christi, also shred their tree waste products to provide an inexpensive form of bulk shredded mulch while reducing debris going into the landfill.
   Other organic mulches sometimes used include pine straw (needles), hay and oak leaves. Grass clippings from healthy, established yards can also be used, but be careful to avoid weed seeds. If you decide to use grass or leaves, you might consider placing a two- to three-sheet thick layer of newspaper below the mulch to reduce light penetration and further assist in weed control.
   Rocky going
   Inorganic mulches such as gravel, crushed stones or river rock are another option but should be used in limited areas. Rock is not the cure-all that many are led to believe. In fact, it actually has many disadvantages that must be weighed before it is selected. Inorganic mulches can increase heat retention, reflect heat and sun glare, increasing your home's energy cost. Gravel and rock areas should therefore be limited to accent areas instead of bulk coverage of areas.
   The increased heat of stone mulches will also cause plants in that area to use water more quickly, thus increasing water use by the plant and negating the water savings for which it was intended. That is one of the reasons why xeriscaping, or "water-wise" landscaping, is not a yard of rock and a few plants. Another problem with rock is that small leaves, seeds and wind blown soil deposit in the small crevices between rocks and provide the perfect environment for weeds to grow. Most weeds in gravel beds do not emerge from the soil below and grow through weed cloth and gravel, but are actually from soil deposits above the weed cloth. If small leaves or soil collects in gravel, it is difficult to remove.
   After looking at the pros and cons of each type, organic mulches surface as the best choice, especially for water conservation.
   Mulching tips
  

Use 3 to 4 inches of mulch for effective weed control. A thinner layer will not work.
  

Using soaker hoses beneath mulch efficiently provides water directly to the root system.
  

Water thoroughly to allow water to move through the mulch to the root system. Sprinkling the surface of the mulch is not sufficient.
  

Don't pile up mulch around the base of trees or shrubs. It may invite fungal problems.
   With the advantages of water conservation, weed control, erosion prevention and soil temperature regulation, it seems illogical not to incorporate mulches into your landscaping scheme. They are easy, inexpensive and give your landscape the finishing touches that will make your yard the envy of all your neighbors.
  
  
2000 Caller-Times Publishing Company, a Scripps Howard newspaper. All rights reserved.