Primetime NewspapersBy Calvin R. Finch, PhD, SAWS Water Resources Director, and HorticulturistWeek of February 27, 2006 
“Valuable Leaves”  

            Leaves, leaves everywhere.  February and March are the months when live oak leaves fall.  It is obvious, based on the number of phone calls we get on the Gardening South Texas Radio Show that not everyone knows that live oak trees lose their leaves every year.  They are not truly evergreen.  The timing of the leaf drop is different from year to year.  This year because of the drought some trees may be dropping their leaves early.

            Raking leaves is good exercise and allows a person to be doing something useful while they daydream.  Letting the garbage collector have the leaves, however, is bad for the environment and bad for our tax rates.  Leaves are too valuable to have them hauled away to fill expensive landfill space.  Use the leaves yourself or at least have someone in the neighborhood use them.  Live oak leaves make great mulch or can be composted in a pile or on the lawn.

 

            The easiest way to use your leaves is to let them decompose where they fall on the lawn.  Unless you have leaves five or six inches deep, they decompose in five or six weeks.  Chop them once or twice with the lawn mower and they decompose in half the time.  The decomposing leaves feed the microorganisms in the soil and provide nitrogen, potassium, and other nutrients. 

 

            If you have a compost pile, live oak leaves make a good addition.  Add a little lawn fertilizer to speed up the decomposition or some of the weeds you are pulling from your garden. 

 

            My favorite use for live oak leaves is as mulch.  Spread four inches deep over the root system of a newly planted tree or shrub and it will speed up growth considerably over a plant where grass grows up to the trunk.  Mulch also makes it unnecessary to string mow near the stems and trunks.  String mowers are devastating on young trees.  Even if the wounds do not completely kill the tree by girdling, they slow down the growth.

 

            After you water your young trees and shrubs this month because of the drought, apply the leaves as mulch to conserve the water in the soil.

 

            Three inches of live oak leaves applied between the rows of the flower or vegetable garden make a pleasant place to walk, reduce compaction of the soil and reduce weeds.  When you plant your tomatoes in April, apply three inches of live oak leaf mulch around the plant (three feet in diameter) to help reduce fluctuations in soil moisture and the resultant blossom end rot.  The symptoms appear because the water stream from the soil is broken when it is hot and dry.  Calcium is taken up by the plant in this water stream.  Any break in calcium during the fruit growth stage and you end up with blossom end rot.

 

            During the period while the leaves are absent you will notice the ballmoss.  Have no fear; it does not hurt the tree.  Ball moss is an epiphyte that makes its living from the air.  It is not sucking the juices from the oak tree.  Ball moss can even grow on fence lines and utility wires.  Enjoy the ball moss; it is a natural part of Central Texas oak growth.  The dead and dying branches in the interior of the crown provide an ideal environment for the ball moss.  The branches are shaded as they are dying and the humidity is relatively high inside the oak crown.