LSU AgCenter Horticulturist
(12/27/19) Cooler weather is perfect for planting trees and shrubs in Louisiana. Fall and winter are both great times, but especially winter. Trees and shrubs slow their growth in winter, particularly the above-ground portion of the plants. Deciduous plants drop their leaves to conserve energy during the cold months. More important, the roots remain active, but at a much slower pace because soil temperatures remain fairly constant throughout the year.
Much like people, many plants slow down during cold winter months. Roots that are largely responsible for moving water, nutrients and gases through the plant will continue to do so. Planting trees in winter gives the plants several months to establish their roots before they begin active aboveground growth. Proper establishment is fundamental to growing healthy trees, and those planted in winter require less water because of lower temperatures and slower growth.
Winter is the best time for planting trees, and pecans are no exception. November through February is as good a time as any.
Pecan trees are very large, growing up to 60 feet tall and 40 feet wide. Keep this in mind before planting.
For one thing, you must have the space for a large tree like this. At a minimum, pecan trees should be planted 20 feet away from any buildings or structures, and farther is better. Pecan wood is relatively soft and brittle, and it is common to find fallen branches during the year.
Pecans are wind-pollinated. The pollen travels pretty far, so if a neighbor has nearby trees, hurray to you. If not, you need to plant at least two to get pecans to make nuts.
A number of recommended varieties for Louisiana are Elliot, Candy, Sumner, Houma, Caddo, Oconee and Melrose, which are more resistant to diseases and are better suited for home landscapes. Plant two different types — Elliot, Candy, Sumner or Melrose with either Houma, Caddo or Oconee are recommended.
Start by planting container-grown trees that are 4 to 5 feet tall. Never allow the roots of the trees to dry out prior to planting. Planting holes should be two to three times the diameter of the root ball and at the same depth as the container. Loosen the root ball when planting, and be sure to remove dead roots or prune them if they have become potbound. Place the root ball of the tree in the hole and backfill around it with the soil you removed from the hole.
As with all trees, it is essential to water heavily at the time of planting and for the next two weeks to get good root growth. It is important to water young trees during extended drought periods, especially during the first and even second summers after planting. Mulch around newly planted trees to help conserve moisture and prevent weeds. Do not fertilize your trees the first year after they have been planted. Beginning year two, trees should be fertilized annually in February. Apply one pound of general-purpose fertilizer per inch diameter of the trunk measured 3 feet from the ground.
Here are some things to keep in mind when growing pecan trees.
Your trees will not make nuts right away. In fact, they will not produce nuts for many years, typically six to 10 years. Trees put all of their energy into their roots as they become established. This is essential. That is why they do not make right away. So be patient, and remember this before you start worrying. Many gardeners are perplexed to discover that their pecan trees have not produced nuts in the beginning.
In some cases, you may have trees that once produced but now have stopped producing or the nuts have little or poor-quality meat. Determining the cause can help you regain good pecan production. It is important to know that healthy leaves are essential for nut production. It takes about 40 pecan leaflets to set and fill out a single pecan nut. During the growing season, foliage manufactures food that is used and stored in the root system for nut production the next spring. Early leaf loss causes a shortage of healthy leaves that limits or reduced nut production the next year. Foliage damage during the growing season can also reduce that year’s crop. Keep leaves healthy, and you will improve your nut production.
Early leaf loss can be the result of a combination of problems, especially scab, a fungal disease that appears early on the leaves and nuts as small black lesions that later enlarge and completely blacken the leaves, eventually killing them and causing defoliation. Scab can attack and damage the shuck or outer covering of the nut and cause a poorly filled or hollow pecan. If you see numerous black spots, streaks or areas on the shucks and the nuts are poorly filled, pecan scab is the problem. Leaf-feeding insects can worsen the problems. Insects such as aphids, mites and fall webworms attack pecan leaves, contributing to early defoliation.
The pecan variety dictates the severity of the scab problem. Many of the older varieties — such as Stuart, Success, Mahan and Desirable — are very susceptible to scab disease. Pecan varieties not considered scab-resistant can be kept in production only through the application of fungicides throughout the growing season. Large pecan trees can be difficult to spray with typical garden equipment available to consumers. Planting disease-resistant trees is your best defense.
My Granny picked pecans every fall, cracked and shelled them with love and mailed them to us every Christmas. Who doesn’t love a good pecan pie or praline candy? Pecan oil is used for cooking and frying foods, offering unique flavor. Pecans are eaten raw or roasted. Pecans are an excellent source of monounsaturated fats, high in fiber and proteins as well as, more than 19 vitamins and minerals — including vitamin A, vitamin E, folic acid, calcium, magnesium, phosphorus, potassium, B vitamins and zinc.
Pecan trees in a grove require significant space between them. Photo by Olivia McClure/LSU AgCenter
Pecan nuts emerge from the shucks. LSU AgCenter file photo by Tom Pope
Pecan nuts. LSU AgCenter file photo