Pecan trees are native to the Midwest, found in river bottom areas along the Mississippi, Missouri, Illinois, Ohio and other rivers. Even the species name reflects their local origin: 'Carya illinoinensis.'
"Growth and nut production are best in these lowland, deep soils," says Tony Bratsch, University of Illinois Extension horticulture educator. "In upland soils and in the home landscape, nut production is variable, but they make large, beautiful and adapted native shade trees. For those who want to consistently harvest nuts, deep soils and adequate summer soil moisture are essential when choosing a planting location."
Pecan trees are closely related to native hickory, and they can be inter-bred resulting in a nut called a "Hican." Pecans are classified into two main groups, the northern and southern types. The southern pecans are also known as "papershell" pecans because of their thin shells. They are widely grown in southern latitudes, requiring a growing season of 200 or more days between frosts to form the nuts. Though attractive trees, they seldom make a nut crop in Illinois, except perhaps in the far southern reaches of the state.
The northern varieties can be grown throughout most of Illinois, but Bratsch says they perform best in central and southern Illinois. Northern pecans have thicker shells and smaller nuts than the southern types. However, they are known for higher oil content and more intense flavor and are preferred for culinary uses.
To ensure a full nut crop, choose early-maturing varieties, and two varieties are needed for cross pollination, says Bratsch. Examples of northern varieties include 'Hardy Giant,' 'Major,' 'Peruque' and 'Colby.' 'Major' is somewhat self-fertile and can produce nuts in the absence of another variety. However, planting two or more varieties is highly recommended. Northern pecan varieties are developed through selection and propagation of promising trees found in the wild. A good source of information about pecan varieties is the Northern Nut Growers Association, http://www.icserv.com/nnga/index.html.
As a native species, pecans generally suffer few problems. However, along with concerns for season length, other conditions can affect nut development. Bratsch says that damage to leaves, such as defoliation by drought, insects or disease, can reduce nut fill. Nutrient deficiency, particularly nitrogen and zinc, is another reason for poor tree growth and nut fill. Zinc micronutrient deficiencies are usually only an issue in high pH soils. When drought conditions occur, trees with a crop of nuts should receive supplemental watering. Plant in lower areas of the property where deep and moist soils prevail, and avoid shallow, poorly drained soils and sites where water stands for long periods of time.
Premature dropping of nuts is another common problem. While poor pollination can be attributed, insect or disease damage can also cause early nut drop. Nut casebearer is a worm that attacks the developing kernel. Pecan scab disease can affect nuts, but northern varieties have some resistance. Both can be managed with appropriate timing of recommended pesticides. Low fertility or drought can also cause premature nut drop.
Pecans mature in mid-fall. They are easy to harvest–simply pick them up off the ground as soon as they drop from the tree. A challenge is harvesting before squirrels and other rodents get them. After harvest, pecans should be "cured" and air dried in a cool, dry, well-ventilated place for two to three weeks. Pecans will oxidize or turn rancid more rapidly when exposed to light and out of the shell; so, leave them in the shell to help retain their quality. Whole nuts can be frozen for up to a year. Cracked nuts should be kept refrigerated and in airtight containers.
Even without a nut crop, pecans are attractive, elegant, large shade trees that can be a pleasant addition to the landscape, especially in open lawn areas where they have space to grow. Avoid planting pecan trees near walkways, driveways or other areas where the dropping nuts can be a nuisance.
Pecans can be purchased as a native seedling tree or as a named, grafted variety. Bratsch says a young tree will transplant more easily than an older tree. As a landscape tree, locally obtained seedling trees may perform better in upland locations. If nut production is the goal, use named, grafted trees since they are more predictable in bearing performance.
For more information about pecans and growing other nut trees, see the University of Illinois publication, "Nut Growing in Illinois," circular 1102 at: http://www.aces.uiuc.edu/~vista/html_pubs/NUTGROW/nuthome.html
Source: Anthony Bratsch, Extension Educator, Horticulture (Serving East-Central and Southeastern Illinois), firstname.lastname@example.org
Pull date: October 1, 2007