WHY MULCH?
  Mulching your plants is one of the best things that you can do for your
plants.  The benefits seem almost endless and can make the worst
gardener a good one.  As seasons change trees drop their leaves and
they pile up.  Over the years forms a natural layer of mulch that helps
keep forest soil cool, moist and reduces soil compaction.  
BENEFITS OF MULCHING:

  1. Retains moisture deducing the amount of water needed.
  2. Keeps soil cool in the heat as much as a 20 degree difference.
  3. Keeps roots protected form freezing.
  4. Prevents weed and grass growth
  5. Allows more microbial activity in soil.
  6. Can be decorative.
BY "THE GURU" ORLANDO MARTINEZ
These benefits cannot be realized if mulching is not done deep enough.  
Too many times I have seen mulch applied too shallow, 1 or 2 inches of
mulch, though looking very nice will not do much.  This holds true for soil
moisture also 1 or 2 inches doesn't do much.
Properly mulching your trees and new shrubs can increase the growth by
50% in the first year of growth.  Mulching allows you a margin of error, if
you forget to water, mulching will allow the plants to make it to the next
rain.
The choice of which mulch really is based on what you think looks nice
and what you can afford.  Remember soil cannot be mulch, compost can,
but not mixed with soil.  If soil is used or soil mixed with mulch the roots of
the plant mulched grow into the mulch and that defeats the purpose.
DIFFERENT TYPES OF MULCH
  • Pine bark - shredded pine bark
  • Hardwood - shredded oak trees
  • Native - mixture of the trees growing in the area
  • Pecan shells
  • Cypress - usually decomposes slowly and doesn't float
  • Cedar - when fresh, has insect repelling properties
  • White marble - works well in cactus gardens
  • Decomposed granite - works well in cactus and low water
    gardens