The pecan tree (\(Carya\) \(illinoinensis\)) is a highly valued nut producer native to North America. The United States is the largest pecan producer globally, supplying a significant portion of the world’s commercial crop. This deciduous tree has been cultivated for centuries, moving from wild river bottomlands to managed orchards across the southern half of the country.
The Native Geographical Home of the Pecan
The pecan’s natural distribution is centered around the Mississippi River Valley and its major tributaries. This native range stretches from the northern states of Iowa and Illinois southward to the Gulf Coast. Wild-growing trees were historically found westward into central Texas and eastern Kansas.
Pecan trees thrived in this environment, particularly on the fertile, moist soils of river floodplains and bottomlands. These areas provided the deep soil and consistent water supply necessary for the trees to establish their extensive root systems. The original distribution highlights the tree’s natural preference for rich, alluvial soil before modern irrigation expanded its growing region.
The Major Commercial Pecan Growing States
Commercial pecan production is concentrated in a handful of states that fall into two distinct growing models. Georgia historically leads production, representing the Eastern model, while New Mexico, Arizona, and Texas dominate the Western model. Oklahoma is also a significant producer, often ranking in the top five states for output.
The Eastern model, exemplified by Georgia, relies on a humid climate and features improved varieties like ‘Desirable’ and ‘Stuart’. This region benefits from higher rainfall, though it also faces greater challenges from fungal diseases, such as pecan scab, which thrive in the moisture. Georgia’s extensive orchards are often managed with a focus on disease control to maintain high yields.
The Western model, prevalent in New Mexico and Arizona, operates in an arid environment with intense sunlight. These growers cultivate varieties like ‘Western Schley’ and ‘Wichita’ and rely heavily on irrigation. This model produces a high-quality nut with less disease pressure due to the dry air, making it a reliable source for high-volume production. In recent years, New Mexico has challenged Georgia for the top spot in total utilized production.
Texas, the state tree of which is the pecan, has a hybrid model, growing both native seedling pecans and improved varieties across its diverse climates. Its production is spread across areas like the Brazos River Valley, benefiting from a long growing season.
The Essential Climate and Soil Requirements
The successful cultivation of pecan trees is limited by specific environmental factors. The trees require a long, hot growing season, ideally lasting seven to nine months, with summer temperatures regularly reaching between 75 and 86 degrees Fahrenheit (24–30°C). This extended period of heat is necessary for the nuts to properly fill and mature before the first frost.
A mild winter is also a requirement, as the tree must accumulate sufficient chilling hours to break dormancy and ensure uniform bud break in the spring. Depending on the cultivar, this requirement can range from 300 to over 1,000 hours of temperatures generally below 45 degrees Fahrenheit. Insufficient chilling leads to staggered and poor bud development, which negatively impacts pollination and yield.
The optimal soil for pecan growth must be deep, well-drained, and capable of retaining water. Pecans develop an extensive taproot system that needs several feet of soil depth to penetrate properly. While the trees can adapt to various soil types, they thrive in deep, fertile alluvial soils, such as those found near river systems. A soil pH range of 6.0 to 7.0 is generally preferred for maximum productivity.