Pecan Nut - Carya illinoinensis

Common Names: Pecan, Pecan Nut, Carya, Pecan Tree, Hickory Nut, Illinois Nut, Nogales, Nueces, Pacana, Pecano, Pékandió, Pekanuss, Pacanier, Pekaanipähkinä, Pecannoot, Orzesznik jadalny, Pikan Cevizi, Ho Dao Pecan, Pokok Pecan, Carya illinoinensis, Pecanus, Global: Pecan, English: Pecan, Latin: Carya illinoinensis, Origin: North America

Latin Name: Carya illinoinensis

Origin: Africa, Asia, Australia, Europe, North America

Short Introduction

Cultivation:

The pecan tree typically grows at elevations of 500–1200 meters above sea level and prefers moist, deep, sandy to clay soils with slightly acidic to slightly alkaline pH, regular watering, and humus-rich earth. It does not tolerate saline soils. While it thrives in full sun, it can endure partial shade, but not full shade.

In the wild, pecan trees often grow alongside elm, honey locust, or poplar near riverbanks in warm, humid climates—ideally, at temperatures of 24–30°C and annual rainfall up to 2400 mm. Although the tree is generally hardy (withstands temperatures down to –28°C), young seedlings should be protected during their first winter.

Before sowing, seeds require cold, moist stratification for 1–2 months at temperatures below 4°C. Germination should take place at room temperature. Seeds must be protected from rodents, and transplanting from pot to pot and then outdoors should be done quickly.

Although pecans were long appreciated as a delicacy by American colonists, commercial cultivation and sale began in the U.S. only in the 1880s. Today, the U.S. produces 80–95% of the world’s pecans, with annual harvests of 150,000–200,000 tons from over 10 million cultivated trees, generally harvested in mid-October.

Historically, Georgia has been the largest producer, followed by Texas, New Mexico, Arizona, and Oklahoma. Other states cultivating pecans include Alabama, California, Florida, Kansas, Arkansas, Missouri, North and South Carolina, Tennessee, and Hawaii. Outside the U.S., Argentina, Australia, Brazil, China, Israel, Mexico, Peru, and South Africa also produce pecans.

The pecan tree can live and bear edible fruit for over 300 years. As the tree cannot self-pollinate due to clonal reproduction, it is advisable to plant several cultivars together to ensure optimal cross-pollination. Pecan cultivation can be challenging for several reasons, notably the slow growth rate, as trees require 15–20 years to begin producing nuts. The most productive years are from 75 to 225 years old, during which a tree can yield about 180–450 kg of nuts annually.

Detailed Description

Pecan nuts are traditional delicacies from the southern regions of North America.

Botanical Information

Pecan (Carya illinoinensis) is a deciduous, monoecious tree that typically reaches a height of 20–40 meters (sometimes up to 44 meters!), with a straight trunk up to 2 meters in diameter. A ten-year-old sapling can reach about 5 meters in height. The bark is dark brown-gray, initially smooth, later becoming scaly with thin surface strips.

The root system is predominantly composed of a long main taproot. The crown is very broad and rounded. The leaves are glossy green, alternate, thin, lanceolate, and pinnately compound, appearing in clusters of 9–17 leaflets, each 10–20 cm long with serrated margins. The undersides of the leaves may be hairy or smooth. Petioles are 5–10 cm long, and the leaf blades are irregularly shaped and ellipsoid. The tree is in leaf from June to October.

The pecan tree flowers from April to May. Male flowers are nearly sessile, yellow-green catkins up to 15 cm long. Female flowers are green catkins up to 7 cm long. Flowers are self-pollinating and wind-pollinated. As noted in cultivation, using multiple cultivars increases both the quantity and quality of the harvest.

Pecan nuts, like all species in the Carya genus, are technically not true nuts but drupes (fruits with a pit or stone surrounded by a husk). The husk is oval to elongated, 3–6 cm long and 1.5–3.5 cm wide. The outer husk, about 3 mm thick, is initially green, gradually turning brown as it ripens and splits into four segments in autumn to release the nuts. Fruits typically ripen in October. The outer husk serves as the fruit's skin, while the actual pecan nut is the pit containing the edible seed. Fruits grow in clusters of 3–12. Pecan nuts have a rich, buttery flavor and are consumed worldwide.

The tree has undergone extensive breeding, resulting in around 500 cultivars that differ in disease and frost resistance, fruit ripening duration, nut size and yield, flavor, oil content, and more. The pecan is botanically closely related to the English (Persian) walnut, widely cultivated in many regions.

Origin and Distribution

The pecan tree is native to Mexico and the central south and southeastern regions of North America, including U.S. states such as Iowa, Indiana, Illinois, Arkansas, Kansas, Kentucky, Mississippi, Missouri, Louisiana, Oklahoma, Texas, and Tennessee.

Its natural habitat is primarily the valleys of the Mississippi River and its tributaries, from Iowa to northern Mexico. The tree has been commercially introduced to other U.S. states and globally to Europe (France, Spain), Asia (China), Australia, and southern Africa.

Usage / Dosage

Pecan nuts are widely used in the food industry in the USA. They can be eaten raw or used in cooking and baking. One of the most popular traditional desserts in the southern United States is pecan pie. Pecan nuts are also commonly found in pralines. Native Americans collected and ate raw pecans, which are sweet and have a buttery flavor. Today, pecans are common ingredients in ice cream, cakes, cookies, confections, and classic baked goods (most popular in bread).

Pecan wood is highly prized for furniture and flooring, and also for flavoring fuel used to smoke meats. Its hard and brittle wood is used for tool handles and vehicle production.

The first Europeans to encounter pecans were Spanish explorers in the 16th century in present-day Mexico, Texas, and Louisiana, naming the nuts 'pecan,' 'nuez de la arruga' or 'wrinkled nut,' because of their resemblance to human wrinkles. Due to their similarity with the English walnut, pecans were often called 'nogales' or 'nueces,' Spanish terms for walnut. Pecans were introduced by Spaniards to Europe, Asia, and Africa during the 16th century.

Historical records from early American settlers mention the pecan tree. Thomas Jefferson planted pecans on his land, and George Washington referenced receiving "Illinois nuts" from Jefferson, which he then planted at Mount Vernon, Virginia. Since 1919, the pecan tree has been the state tree of Texas, with San Saba recognized as the 'pecan capital of the world.'

Pecans were widely consumed and traded. Traditional folk medicine among Native American tribes used not only the nuts but also the bark and leaves for their astringent effects on the digestive tract. Crushed nuts were made into a paste to treat infectious skin lesions (caused by dermatophytes).

Uncontrolled high plasma cholesterol can lead to cardiovascular issues. Regular consumption of pecan ingredients has been shown to support a healthy plasma cholesterol profile among healthy volunteers and medicated patients. Researchers such as Rajaram S. et al. recommend regular inclusion and prescription of pecans (especially due to their monounsaturated fatty acid content) with a low-calorie, low-fat diet for patients with high cholesterol.

Consuming nuts like pecans regularly appears to positively influence glucose levels in both healthy individuals and patients with diabetes. High blood sugar, like high cholesterol, is a risk factor for cardiovascular disease, so a healthy diet rich in nutrients and minerals is recommended. Studies have shown reduction in plasma blood sugar following regular pecan consumption and suggest that pecans may lower the risk of type 2 diabetes.

The active compounds in pecans (particularly antioxidants such as vitamin E, fatty acids, and proteins) may help delay and reduce risks of cardiovascular diseases, have a protective effect and reduce the risk of high blood pressure. A high tannin content may explain why pecans are associated with prevention of a wide range of diseases, including cancer.

Other compounds in pecans (notably tocopherol and flavan-3-ol monomers) help inhibit oxidation of free lipid particles in the bloodstream, thereby providing protective and preventive effects against heart disease. Studies of antioxidant capacity, catechins, and reduction in LDL oxidation indicate that pecans may contribute to postprandial antioxidant defense.

Pecans also increase satiety due to their fiber and protein content, which can help reduce food intake. This effect has been used in traditional medicine for weight management and appetite control.

The antioxidants in the outer layer of pecans are able to neutralize small doses of cyclophosphamide, which is linked to the development of certain heart, kidney, and bladder diseases, suggesting that pecans may reduce the risk associated with cyclophosphamide toxicity.

Active Compounds

Pecans contain proteins, amino acids, tannins, fatty acids, starch, fiber, and monosaccharides, contributing to their high energy value. Vitamins include riboflavin, niacin, thiamin, beta-carotene, folic acid, pantothenic acid, vitamins A, E, and K. Minerals include phosphorus, magnesium, zinc, sodium, iron, calcium, copper, manganese, and selenium.

Traditional Dosage

No standardized recommended dosage for pecan nuts is available.