Tall and leafy, the pecan tree (Carya illinoinensis) is a welcome addition to your landscape for its beauty and shade. An added bonus is the harvest that you may enjoy by the end of fall. Caring for pecan trees, hardy in U.S. Department of Agriculture plant hardiness zones 5 through 9, in the fall is particularly important, especially if your goal is a bountiful harvest. The nuts need consistent, generous irrigation to fill their hulls and develop a high-quality pecan. Making sure that the tree has the water and growing environment it needs -- and trying to protect it from animals who want to get to the nuts before you do -- is a vital part of fall care.
Remove debris from under the tree and keep the grass mowed throughout the fall. The area around the tree needs to be clear in preparation for October's harvest. The nuts fall onto the ground and need to be retrieved quickly -- an easier process if the area remains clean. Removing debris also eliminates attractive areas for insects preparing to overwinter.
Irrigate the trees well throughout the fall. Each mature tree needs approximately 200 to 350 gallons of water a day in the two months before harvest begins in October for optimal nut growth. Adequate moisture is necessary for nuts to fill their hulls; too little water affects the size and quality of the nut, and has an adverse effect on the development of leaves and shoots.
Prevent weeds from growing near the tree so other vegetation does not usurp the tree's moisture and nutrients. Keep a 4-inch layer of mulch around the tree to about 4 feet from the trunk. Leave a space of 6 inches between the mulch and the trunk so you do not unwittingly provide shelter for pests and rodents that would damage the tree. Hand pick or hoe weeds that grow through the mulch.
Protect the trees and nuts from squirrels -- they are the greatest animal threat to a successful fall harvest. Squirrels not only break twigs but just one can eat up to 50 pounds of pecans every fall. Live traps with peanut butter bait may cut down on squirrel damage, but squirrels are difficult to avoid if your pecan tree is accessible from nearby branches.
Harvest nuts immediately. They are ready when they fall off the tree when you shake the branches. Use a long pole to shake upper branches, and pick them up quickly. Leaving them on the ground attracts birds and animals, and leaving the inedible outer hull on the nut too long after it ripens decreases the nut's quality.