Osage Pecan Trees

Climate and Shuck Split

• Pecans like summer temperatures of 75 to 85 degrees Fahrenheit and will tolerate temperatures of 105 to 115 degrees. Pecans like winter temperatures of 45 to 55 degrees but will survive plunges to minus 20 degrees. Native to moist bottom lands mainly along the Mississippi River and its tributaries and the Colorado River in Texas, they are found naturally from Iowa south to Texas and Indiana and Kentucky south to Alabama. A pecan "shuck," or nut cover, eventually splits, revealing the nut inside. Pecans appropriate for colder climates split earlier than those better suited for warmer areas. Shucks should ideally split at least one week before the average first autumn frost. “Osage” shucks split in early September. Most cultivar shucks split in mid to late October.

Nut Size

• The size of pecans is measured by the number of nuts in 1 pound. There are 81 small “Osage” nuts in each pound. In comparison, there are 38 large pecans in 1 pound of “Surprize” (Carya Illinoinensis “Surprize”) and 48 nuts per pound of “Gloria Grande II” (Carya Illinoinensis “Gloria Grande II”) and “Oconee” (Carya Illinoinensis “Oconee”). Most cultivars have 50 to 55 medium-sized pecans per pound.

Alternate Bearing Tendency

• Pecans have a tendency to bear a large crop one year followed by few or no nuts the next year, called biennial or alternate bearing. Some late-bearing trees that yield large nuts use so many carbohydrates to produce nuts there is not enough left for the tree to develop flowers and nuts the next year. “Osage” yields small nuts in early to mid-September and has a low tendency for alternate bearing.

Scab Fungus Resistance

• The pecan scab fungus (Fusicladium effusum) attacks leaves in the spring and nuts during the summer. Infections can strip the tree of leaves and infect shucks resulting in small, poorly filled nuts. University of Alabama horticulturists rate the pecan scab resistance in four categories: poor, moderate, good and excellent. They rate “Osage” resistance as good.