HOME FRUIT PRODUCTION - PECANS
John A. Lipe, Larry Stein, George Ray McEachern, John Begnaud and Sammy Helmers
Extension Horticulturists
The pecan is the Texas state tree, being native to about 150 counties and capable of growing and producing in all Texas counties. The tree is popular for landscaping and as a source of nuts. Proper attention to cultural requirements and pest control will help to assure a long and productive life for home pecan trees.
Soil and Site Requirements
Pecans are native to river and creek bottoms, the soils of which are deep, fertile and well-drained and have substantial water-holding capacity. Pecans require at least 3 feet of well-drained soil above the minimum depth of the water table to develop a strong root system. Pecans planted on shallow soils having poor internal drainage never develop into large, productive trees.
Attempts to modify shallow, poorly drained soils by digging large planting holes and filling them with topsoil seldom work. At best, this is only a short-term solution. Often the topsoil-filled hole will retain excess water, causing the tree to grow poorly or die. The planting site should have good surface and internal drainage, receive full sun and be at least 30 feet from a building, other trees or a power line.
Purchasing Trees
Nursery trees are available as either container grown, bare root or large tree transplants. Purchase trees from a reliable nursery source. Avoid "bargain" trees from outlets not equipped to provide good protection from excessive heat, drying and freezing. Purchase trees as soon as they are available at a local nursery or order them at least 6 months ahead of planting from a reputable mail order nursery.
Bare Root
These trees are the most common pecan nursery trees in Texas. They can be difficult to transplant and need careful handling to prevent transplanting death or slow growth. Protect their roots from freezing and drying. Tree size is important; avoid trees smaller than 4 feet tall, and more than 8 feet tall.
Container Grown
These trees are usually smaller, can be planted anytime and are better bets to live and grow well. Container trees are growing in popularity but are less available.
Large Tree Transplanting
A significant number of large, mechanically dug, pecan trees have become available in Texas in the last 10 years as commercial orchards thin out trees to correct crowding problems. The purchaser may think that these trees will provide instant landscaping; however, this is seldom the case. They require excellent soil, very frequent irrigation and seldom decrease the development time over bare root trees. Large transplanted trees also are expensive.
Varieties and Seedlings
Pecans do not come true from seed, and every native or seedling pecan tree is distinctly different from the seed parent. Over the years, more than 1,000 pecan seedlings have been named and grafted as varieties. Only a very few of these have become established as outstanding varieties.
Seedlings
These ungrafted trees make good landscape trees because they characteristically have strong, fast growth and a natural central leader without training. Nut quality is variable but at least acceptable. Seedlings usually are better in structure and appearance than improved variety trees. Seedling trees rarely bear nuts as early as improved varieties.
Improved Varieties
If nut production and kernel quality are the major objectives, plant grafted varieties. They differ greatly in nut quality, size and attractiveness as shade trees, so growers need to select the specific variety for their needs.
Over the years, varieties have been identified which performed well in various areas of Texas. These are listed in Figure 1, with the most recommended varieties listed first.
Pollination
Commercial pecan growers must pay special attention to cross pollination; however, neighborhood trees can supply the needed pollen unless landscape trees are very isolated. Pecan varieties do only a fair job of self pollination because some varieties shed pollen early (before female flowers are receptive) while others shed late (after female flowers are receptive). Fortunately, there are good early- and late-pollen-shedding varieties available to ensure effective cross-pollination. Pecans are wind-pollinated and can cross-pollinate with trees up to 1/4 mile away.
Ideally, pecans should be within 300 feet of another variety or a native tree. If inadequate pollination is probable, plant at least one early- and one late-pollen shedding variety in your landscape.
Early-pollen-shedding Varieties
Desirable is an outstanding variety for the humid areas of east and south Texas and also produces well in central Texas. The tree grows fast but requires at least 8 to 10 years to bear 15 pounds of pecans. It has weak "V" limb angles which require training and its foliage is light green rather than a more attractive dark color. Scab resistance is moderate and can be controlled with fungicide sprays. Desirable is not an exceptionally heavy bearer, but as an older tree it is the most regular producer of crops of high quality pecans. Nuts/lb - 39; percent kernel - 54.
Western can grow and bear nuts with less management than any other variety in the far west. The tree is strong, easy to train and productive, coming into production in 7 to 8 years. Western is highly susceptible to scab disease and should be grown only in west Texas. Nuts/lb -52; percent kernel - 59.
Pawnee is a new, extremely early-ripening variety recommended especially for the Texas Panhandle. It is a medium-size pecan with good kernel quality. Additional years of evaluation are needed before recommending it for all of Texas. It appears to have a natural resistance to aphids, which are a leading pecan pest. Nuts/lb - 50; percent kernel - 58.
Caddo is an excellent yard tree in all of Texas because of strong limbs, scab resistance, early ripening and attractive foliage. Its nuts are very small but have high-quality kernels. The trees begin to bear in 5 to 6 years and tend to bear well annually. Nuts/lb - 63; percent kernel - 57.
Cheyenne is a very productive, smaller tree which begins to bear a high quality nut in only 5 to 7 years. Cheyenne is particularly susceptible to aphids. It can be grown in all but the northern panhandle area of Texas. Nuts/lb - 51; percent kernel - 57.
Cape Fear is a good yard tree for east and south Texas because of its strong, easy-to-train limbs, high yield and scab resistance. The trees begin to bear in 5 to 7 years; however, the kernels are only fair quality and the foliage is highly susceptible to fungal leaf scorch. Nuts/lb - 47; percent kernel - 54.
Oconee is a 1989 USDA release that has good potential for east Texas and the Gulf Coast. It has very good disease resistance and large nuts of about 56 percent kernel. It is suggested for trial only.
Houma is a 1989 release that has good potential for east Texas and the Gulf Coast. It has excellent disease resistance and medium size, high-quality nuts with nearly 55 percent kernel. It is suggested for trial only.
Late-pollen-shedding Varieties
Sioux is an outstanding yard tree because of its strong, easy-to-train limb structure and extremely high-quality, small nut. It has moderate scab susceptibility and will require fungicide sprays during periods of high humidity. Nuts/lb - 62; percent kernel - 59.
Wichita is the most productive pecan grown in Texas and is ideally adapted to central and west Texas. Although it has serious scab problems in the humid areas and freeze problems in the far north, the tree is very vigorous, productive and begins to bear in only 5 to 7 years. Wichita develops "V" limb angles that split and require careful training. It tends to be a poor-bearing, unattractive tree if it is not well managed.
Choctaw is a good yard tree because of its beautiful foliage, scab resistance and high yields of large, high-quality pecans. Unfortunately, Choctaw requires the very best soil and management; otherwise, it will fail. Nuts/lb - 38; percent kernel - 59.
Tejas is a good yard tree for west Texas. The tree is extremely vigorous and large, producing small leaves and good-quality pecans. It is highly susceptible to scab disease and should be grown only in the drier areas of the state. Nuts/lb - 59; percent kernel - 53.
Kiowa is a newer variety that has good limb structure, attractive foliage and large nuts. It begins to bear at about 6 years of age and bears good crops, but nut quality has been inconsistent. Nuts/lb 39; percent kernel - 57.
Forkert is an old Mississippi variety that is little known, but rapidly gaining popularity in Texas because of its excellent nut quality. Nuts/lb - 42; percent kernel - 63.
Maramec is a fair-quality, large pecan which has produced strong trees and consistent production in Oklahoma. It is recommended as a yard tree for north Texas. Nuts/lb - 42; percent kernels - 58.
Mohawk is a fair yard tree for north Texas. It matures early - ahead of fall frosts - and has strong limb structure and beautiful foliage. It bears heavily, but like other varieties with very large nuts, the nuts are poorly filled as the tree ages. Nuts/lb - 33; percent kernel -59.
Shoshoni is an early ripening variety for the Panhandle and north Texas. The tree is very productive and begins to bear in only 5 to 6 years. It begins alternate bearing at an early age, which limits its usefulness as a yard tree except in the colder north where later maturing varieties are vulnerable to fall freeze injury before the nuts mature. Nuts/lb - 43; percent kernel - 54.
Burkett is an old variety that is common across Texas, but is recommended only as a yard tree in west Texas. Do not plant Burkett in the rest of Texas because of disease and insect problems. Nuts/lb - 42; percent kernel - 59.
Planting
Bareroot pecan trees can be planted from December through mid-March in most of Texas. It is important that roots remain slightly moist, but not wet, at all times between nursery digging and planting. If you are not ready to plant at the time of purchase, "heel them in" by placing the roots in a trench or hole and covering them with moist soil.
Trim off all broken roots immediately before planting.
Container-grown trees can be planted anytime of the year but fall or winter planting is best to give time for the trees to adjust to their new environment before hot weather. Don't confuse trees that have the roots packaged in a plastic sleeve filled with potting soil with container-grown trees. Trees packed in plastic sleeves should be handled as bare root trees.
Because container trees are grown in soilless media, at least 1 inch of this medium should be washed off the root ball with a garden hose prior to planting. This places the exterior roots in direct contact with the planting soil in which they must live, thereby aiding in adaptation to the new environment. Also, 1/2 to 1 inch of soil should be placed over the top of the root ball after planting to seal off the artificial medium and prevent it from drying too rapidly.
Dig the planting hole only as large as the root system (Figure 2). Extra deep or large holes back-filled with soil allow the tree to settle. Settling or planting too deep can cause root damage that results in poor growth or death of the tree. To avoid settling, rest the base of the taproot firmly against the bottom of the hole. If the hole is at least 2 feet deep and the taproot is longer, cut the taproot off to fit the hole.
Plant trees at the same depth at which they grew in the nursery.
The soil line on bare root trees can be determined by the color of the bark. The trunk is gray and the root is dark brown. If the hole is too deep and the tree settles after planting, lift the tree to the original soil line before growth begins.
Firmly pack the soil around the roots in 2- or 3-inch layers as the hole is filled to eliminate air pockets. Fill the hole with topsoil from the planting site. Do not fill the hole with sand or potting soil, especially in poorly drained clay soil because the light soil in the hole will become water-logged during rainy periods. Water saturation of the soil can result in major root damage and often tree death.
Thoroughly water trees with at least 5 gallons of water immediately after planting. A 3- to 5-foot diameter watering ring of soil around the tree will help hold the water as it soaks into the ground.
Cut bareroot trees back by one-half at planting (Figure 2). Trees not cut back are at much greater risk of death or poor growth. Container-grown trees do not need to be cut back as much, but if the trees are placed in a low-maintenance landscape, cutting back improves the rate of survival.
Spacing
Pecans develop into large trees with massive root systems, and should be planted at least 35 feet apart. Trees planted too close develop poor health, have unattractive shapes and, as crowding occurs, nut production and quality are poor. Moisture and air cannot reach roots under concrete, so plant trees at least 15 feet from driveways or foundations.
Training Young Trees
Grafted pecan trees need to be trained to develop one single central trunk with strong, wide-angle branches (Figure 3). Untrained, grafted trees usually develop several trunks which have narrow branching angles with trapped bark between "V" limbs. These narrow forks are weak and prone to split under high winds, water, ice or a heavy crop.
Young trees must grow rapidly for training to be successful; therefore, delay training weak trees until rapid growth is stimulated. Ungrafted native or seedling trees usually form one central leader naturally with little or no training.
Tree training steps are simplest to understand if each objective is considered separately.
Remove Extra Leaders
Remove all but one central leader on the tree. Young grafted pecan trees frequently have two to five leaders developing from one point on the trunk. All but one vertical trunk will need to be removed. When removing the multiple leader, use a collar cut (no stub, but not so close as to remove the visible collar at the base of each branch) at the point where the leader meets the trunk.
Heading Back the Central Leader
Cut off one-half of the central leader (Figure 3) before growth begins in April. This cutback will result in several shoots developing just below the cut. Each spring for the first few years, select and leave the strongest of these vigorous, erect shoots to become the new central leader and remove the other shoots arising within 6 to 8 inches of the cutback. This central leader will grow rapidly once the others are removed.
Trashy Trunk
Small limbs on the lower trunk are beneficial for food production and rapid root development. Permanent branches are developed beginning 6 feet above the ground. Keep the side shoots on the lower trunk short by pinching out their growing point.
Do this two or three times a year, as needed, to maintain the trashy trunk (Figure 4). Remove branches on the lower trunk, using a collar cut (Figure 3) when they reach 1 inch in diameter at the base.
Scaffold Branches
These are the branches 6 feet or higher above the ground from which you will select permanent limbs. Keep in mind that where choices can be made, it is always best to leave branches with wide crotch angles. Limbs with crotch angles between 45 and 90 degrees are much less likely to split out than limbs with narrow "V" crotch angles. The key is to check for trapped bark between the side limb and trunk (Figure 5). If bark is trapped, the limb will always have a weak attachment to the trunk and it should be removed. It is best if permanent scaffold branches are at least 2 feet apart. If the tree has too many branches, prune as needed to thin out crowded limbs.
Pruning Mature Trees
Large pecan trees seldom need major pruning. Late winter when the trees are dormant is the normal time to remove dead wood, low hanging limbs or branches that are in the way, endangering structures or power lines. However, pruning can be done anytime it is necessary.
Tree Topping
The all-too-common practice of severely topping (Figure 6) pecans and other trees is not recommended. Severe topping of a healthy tree ruins its looks and can allow insect and disease entry that may kill the tree. Also, the new limbs developed after topping usually have narrow branching angles and are easily split out.
Tree Thinning
If tree crowding occurs with age, whole trees should be removed. Pruning will not correct for root and limb crowding. Pruned trees will grow rapidly and soon crowd again.
Fertilization
Young Tree - Nitrogen
Nitrogen is necessary for rapid tree growth and is the only soil-applied nutrient that most pecan trees ever need. It is important to apply nitrogen in frequent small amounts during the first few years.
Spread fertilizer on the soil surface, under the tree, but well away from the trunk. Nitrogen fertilizers are very soluble and are readily moved into the soil by watering. It is inefficient and unnecessary to make holes around the tree to pour the fertilizer into the ground.
If the trees are not making rapid growth, do not fertilize the first year. Poor growth by a first-year tree usually indicates problems other than lack of nutrition, and fertilizer may hinder rather than help the tree.
Ammonium sulfate (21-0-0) and ammonium nitrate (33-0-0) are common, economical nitrogen fertilizers that can be used. Table 1 gives guidelines for determining how much fertilizer to apply and when.
Freeze damage is very common on young pecan trees fertilized after the month of June, so do not fertilize after this date.
Table 1. Cups of ammonium sulfate or ammonium nitrate per tree.*
