Right Plant, Right Place!

In the middle of a West Texas July, I drink copious amounts dihydrogenmonoxide.  I'm a native West Texan, so I poke fun at my oldest daughter, when she occasionally makes the summer trip from Cape Cod, Massachusetts to Midland for a visit.  She's accustomed to the cooler weather and higher precipitation of the Eastern seaboard.

For large woody plants such as trees, a similar visit would spell certain disaster.  Whoever heard of a sugar maple in West Texas.  They can't go indoors to cool off for a spell nor can they grab the garden hose at will to replenish their scorched foliage.  Even if they could, the salts in our water would pitch them into shock.  This over simplified analogy illustrates several reasons West Texas landscape plants need to be adapted or native to the region.  The most important of these is water.

The single most important limiting element that determines the survival of a plant is water.  Plants that are physiologically adapted to survive in regions of abundant rainfall will not perform well in the Permian Basin in the long haul.

No more common question is reaching the ears of arborists in West Texas right now than “how can I save my trees?”  We've seen the removal of hundreds of dead and dying trees for a couple of years now.  Few of these trees have been lost to insect pests and fewer still met their demise from fungal diseases.  Usually, these pests secondarily attack weakened trees. 

Trees that are maladjusted or non native to West Texas have been hanging on by tenuous threads of luck for many years and when the drought struck, their luck ran out.  One problem with planting a non-native landscape tree in the Permian Basin is that it typically has a high demand for water. 

Let’s consider trees in the true willow family.  Willows are native to a region in China that has a constantly damp clay soil and receives an average of about twenty-five inches of rainfall annually.  Willows are fast growing weak-wooded trees which are easily damaged in high winds and ice storms.  They can expect a healthy life span of about thirty years under optimal conditions.   After thirty years, they may hang on for many years in various states of decline.

Obviously Willows can be forced to grow in our poor soils and extreme heat as long as enough water is provided to supplement the thirteen or fourteen inches of precipitation we expect to receive every year.  But when the precipitation drops below projected amounts and supplemental irrigation is limited to two hours per week, trees with high water requirements such as willows, begin to agonize.  This same scenario is true for Silver maple, Mulberry, Sweet gum, poplar, Sycamore and a host of others not well adapted to conditions in the Permian Basin.

Now let’s consider another tree which is native to China that does well in the Permian Basin.  Chinese pistache is native to a region in western China that receives rainfall averages between 0.6 inches to 7.9 inches annually.  These conditions are similar to ours which is one reason Chinese pistache performs well in West Texas.  While it’s not native to Texas, it is adapted. 

If you already have a mature non-native tree on your property don’t give up on it just yet.  Many such trees can be drought hardened, to an extent, by slowly cutting back on the amount of water they receive over the course of several years.   The goal is to encourage the development of a root system that extends its reach further out into the surrounding soil.  Another way to keep these trees is to get more water to them by collecting and storing rainwater (see earlier posts) for use later.