Dear Friends,

This is the 13th issue of our weekly gardening newsletter for Houston, the Gulf Coast and beyond. This a project of The Lazy Gardener, Brenda Beust Smith, John Ferguson and Mark Bowen (both John and Mark are with Nature's Way Resources). We also have a great cast of contributing writers who will chime in regularly. We would love to keep receiving your input on this newsletter . . . . comments . . . . suggestions . . . . questions. . . .Email your thoughts to: lazygardenerandfriends@gmail.com. Thanks so much for your interest.

Enjoy!

For correspondence that is specific to Brenda, feel free to email her directly at lazygardener@sbcglobal.net. 

MULCH CORNER                  

                 

 

BY JOHN FERGUSON

 

 

This week I had a customer ask me why we recommend organic mulches over shredded tires or gravel.  These have their place and will be discussed in future articles.

 

Why Organic Mulches:

 

Organic mulches offer the most benefits, often at lower cost, and improve  the fertility and health of the soil. 

 

A three inch layer of organic mulch can lower soil temperature about 25-30�F which reduces plant stress and water requirements. Bare soil can easily reach 100-135 �F which speeds evaporation and dries out the soil, stresses the plant resulting in wilting, causes insect and disease problems and in most plants eventual death.

 

The higher soil temperature reduces a plants roots ability to absorb moisture (even if it is there) and the higher temperature kills beneficial microbes that help feed, water and protect the plant's roots.  In addition, soil nitrogen (N) decreases as soil temperatures increase. For every 100�C increase in soil temperature, soil nitrogen (N) will decrease 2-3 times. 

 

Studies in Austin and San Antonio Texas during the 1990's found that lawns mulched with 1/2 inch of compost each year, saved $50-$200 per month on their water bill. See photo below.

 

Plants grown in organically enriched soils suffer far less disease and insect problems than plants grown with synthetic chemicals. Thus good organic mulch helps build up the soil, naturally increasing a plants pest and disease resistance.

 

Two studies from Ohio State University have confirmed that plants grown organically in organically enriched soil suffer far less disease and insect problems than those grown with synthetic chemicals. Therefore good organic mulch helps build up the soil, naturally increasing a plants pest and disease resistance.

 

USDA studies on several species of plants have found that mulched plants were often 3 times as large and produced 3 times the yield of un-mulched plants after several years.

 

In January of 2011 the yard on the right went organic using leaf mold compost as a mulch and the Microlife organic fertilizer. Both yards were under water restrictions during the severe drought.  The photo was taken by T. Polk, owner of Mother Nature Landscapes, whom did the work. 

 

 

 

 

Tip Of Week: Volcano Mulching

 

Since  we have been discussing mulches it seems time to discuss the practice of pilling mulch up on the trunk of a tree that is commonly called "volcano mulching".  It is very harmful to the tree and this practice is illegal in many states!

 

A tree has two types of bark on it.  The first is the rough bark that is above ground.  It is naturally  resistant to fires, insects, and microbial degradation and is designed to protect the tree in a dry environment since it is above the ground.  The other type of bark is on the roots and tends to be smoother, thinner, and built to survive in a moist environment (e.g. the soil).

 

When one places a pile of mulch around the root flare and trunk of the tree, it creates a moist environment that the bark cannot withstand for a long period of time.  The bark softens from the moisture and is attacked by all sorts of life from insects and disease to rodents that can now eat the bark. 

 

Corrupt or ignorant landscapers like to do this as trees slowly weaken from the stress over time. As the tree weakens it may develop disease or insect problems.  The landscaper then can sell the customer a "treatment" for the problem as they now earn extra money.  This may go on for a year or two and then the tree eventually dies. Now the landscaper can sell you a replacement tree and collect hundreds of additional dollars of your money.

 

Hence when mulching always make sure the flare and truck of the tree ARE NOT covered with mulch (or soil).

 

When choosing a landscaper always ask them to show you pictures of their work.  If they have mulch piled around the trunk choose someone else to do your work.

 

The picture below is from Howard Garrett showing a tree that has died from having its trunk covered. Notice how the bark has rotted away.

 

 

 

 

 

Bayou Planting Guide helps your garden grow: Five foolpoof plants that thrive in the Houston climate  http://houston.culturemap.com