Since April is National Pecan Month and April 14 is National Pecan Day, it seemed appropriate to discuss pecans and their care a bit.
The pecan is not only the state tree of Texas but also is native to 150 counties in the state. Pecan trees are among a few plants that can have both landscape and commercial functions. 
If you are contemplating adding pecan trees to your landscape, remember that for optimum results pecan trees should be dug and transplanted during the dormant season of December, January and February. The trees require full sun and should not be planted close to other trees or buildings that can shade them. There are two patterns of flowering in pecan trees. One produces pollen first (protandrous) and the other produces the pistillate flower or nutlet first (protogyhnous). Early and late pollen-shedding varieties should be planted together to ensure effective cross-pollination for a good nut harvest. Pecans are wind pollinated and can cross-pollinate with trees one-quarter mile away. For consistent pollination, however, trees should be within 300 feet of a pollinator variety or native tree. 
Pecan trees are survivors and can live with little or no care in much of Texas. However, if the tree is expected to look good as a landscape tree or if it is expected to produce high quality nuts it can become a high maintenance tree. Even though the pecan is adapted to the hot, dry, windy Texas climate and tolerates stress, there are many things that can damage or kill a mature bearing pecan tree. In most cases there is a combination of factors that kill the tree.
According to the Extension Horticulturist at Texas A&M, planting improved, grafted varieties in poor soil is the most common reason pecan trees die in Texas. Un-grafted, grown from seed (seedling) trees usually make good landscape trees and with minimal landscape management these seedling trees do better than the improved varieties which have been developed for optimal nut production or stress resistance. The pecan is native to river and creek bottoms where the soil is deep, fertile and well-drained. Planting pecan trees in soil that does not drain well makes them susceptible to Cotton Root Rot because of the excessive moisture retained around the roots.  Pecans do not tolerate standing in water, nor do they tolerate severe drought conditions. Trees should be watered regularly from April through September. Each watering should be sufficient to soak the soil to several inches deep. Studies have shown that most of the feeder roots that take up water and nutrients are found in the first eight to twelve inches of the  soil. 
Inadequate zinc supply can cause stunted leaves and reduced terminal growth. This can be corrected by foliar applications of zinc. Soil applications have not been satisfactory or economical in the past in West Texas. Zinc solutions should be applied thickly enough that it drips off of the leaves. It is worth noting that zinc solutions can burn the leaves of other trees. Nitrogen fertilization is also necessary for a healthy tree. Nitrogen fertilizers are most effectively applied to the soil in an area approximately 50 per cent larger than the width from the trunk to the drip line. Lack of insect or disease prevention can also fatally damage a tree. The trees are especially susceptible to these factors when combined with an especially heavy crop on trees growing in poor soil. 
The major portion of this information came from several publications of the Texas A&M Extension Service. If you are interested in additional information, the Stephens County Extension Service has other publications available that address such topics as planting pecan trees, grafting, commercial production, insect control and spray schedules for zinc and insecticides as well as fertilization schedules. 
If you have questions or comments, please respond to greensideup2@hotmail.com. Share experiences or enlighten the rest of us with new ideas, in regards to Pecan trees and their nurturing during the drought season we are experiencing. 
“April hath put a spirit of youth in everything.” -  William Shakespeare