Size, Height & Width of a Mahan Pecan Tree

Size and Habit

• “Mahan” pecan trees are deciduous and thrive in U.S. Department of Agriculture plant hardiness zones 5 through 9. They are native to Mississippi. “Mahan” has a symmetrical crown of thick, heavy, dark green leaves that grows in a rounded, umbrella shape.

Height and Width

• Pecans are vigorous growers and mature into large shade trees. “Mahan” reaches 70 to 100 feet tall, depending on its growing conditions. The width of its crown ranges from 40 to 75 feet. Soil drainage and depth are important factors in pecan tree growth, as is regular, deep watering during the tree’s first few years. Fertilizer shouldn’t be used until the tree is several years old.

Pruning and Training

• Train pecan trees to a central leader system, having a main trunk growing vertically with horizontal scaffold branches every 8 to 16 inches. For good nut production and ease of harvest, limit the height of the tree to about 40 feet tall, topping it by cutting to an outward lateral branch about the same size as the central leader portion being cut. Production decreases when trees are allowed to reach full size.

Pollination and Nuts

• Pecan trees are self-fertile, producing male and female flowers on the same plant. The female flowers appear on the current season’s growth. The male catkins grow on wood from the previous season. However, planting a different pecan variety, such as “Desirable” (Carya illinoensis “Desirable”), helps ensure better pollination and nut production for “Mahan.” This variety’s large nuts reach up to 3 inches long and ripen in mid-November, which is late in the pecan season. They have thin shells that crack easily.