Information about pecan trees

Scientific Name: Carya illinoinensis (Wangenh.) K. Koch

Pecans are part of the Walnut family of Juglandacae.
They are large, deciduous trees that can grow over 100 feet tall.


"The pecan nut has a smooth shell, bottom left. Next to it is the meat of the nut. A husk encloses each nut, far right."
                  From the World Book.  Illustration by Kate Lloyd-Jones, Linden Artists Ltd.

"Pecan is usually found in the deep rich soils associated with streams and river bottoms in East and Central Texas but it has been widely planted across the state outside its natural range.  Pecan wood has a light reddish-brown sapwood and a darker heartwood.  It is not as strong as other hickories and is used primarily for flooring and veneer for paneling and furniture.  This is the largest and fastest growing hickory and has become widely cultivated outside of its natural range for the nutrient-rich nuts.  It is relatively free of serious pests and diseases but it is hard to transplant because of the long taproot.  Webworms can be a problem on some trees.  The nuts were a favorite food of the Indians and are an important food source for many wildlife species.

Pecans used to be so abundant that large trees were often cut down to harvest a single nut crop.  This short-sighted, wasteful practice illustrates how some of Texas' virgin forests were exploited for profit.  The leaves and bark have been used medicinally as an astringent.  It is rumored that the high tannic acid content of the leaves inhibits growth of some plants beneath the trees.  Pecan is the state tree of Texas.  The state champion Pecan is located in Franklin County and is 111 inches in circumference, 115 feet tall, and has a crown spread of 66 feet.

Leaves: Alternate, compound, 12-20 inches long with 9-17 leaflets that are 3-8 inches long and 1-2 inches wide.  On top they are smooth to slightly hairy and dark yellow green, slightly paler beneath.

Flowers: In spring, both sexes on the same tree.
Male catkins 5-6 inches long, female flowers in short terminal spikes.

Fruit: Ripening in the fall, in clusters of 3-11.  The husk is thin and splits into four sections and often stays on the tree after the nut has fallen.  The nut is light reddish brown with irregular black or darker brown blotches.  The meat is edible, sweet and oily.

Twigs: Stout reddish brown and hairy, terminal bud almost 1/2 inch long, flattened and pointed at the tip.  Lateral buds smaller, hairy, broadly cone-shaped and pointy.  Leaf scars are three-lobed and prominent.

Bark: Thick, light brown to reddish brown, with narrow, irregular fissures, flattened and scaly."

Quotation from "Texas Trees: A Friendly Guide" by Paul W. Cox and Patty Leslie.
Published by Corona Publishing Company of San Antonio, Texas.  Copyright 1988.

Pecans grow on angiosperm trees, meaning that the trees flower once a year and bear the seeds inside a fruit.  Gymnosperm trees, such a the Loblolly Pine (Pinus taeda), produce unprotected seeds carried on cone scales.

The pecan tree became the state tree in 1919.
Governor James Hogg requested that a pecan tree be planted at his grave.

If you are considering planting new pecan trees in a residential setting
or want information about the ones in your yard, click here.

Curious about commercial orchards in Texas?  Then click here.

The following is a wonderful summary about the debated scientific name for pecan trees. L. J. Grauke is a very well-respected and published horticulturalist working with the USDA and Texas A&M University. The full link is here:

"There is still apparently some confusion concerning the most appropriate scientific name for pecan: Carya illinoensis, or C. illinoinensis. As one who has been involved in the debate, I would like to offer clarification. Most horticulturists use the spelling illinoensis. In fact, that spelling is specified in the ASHS Publications Manual (1991). This is consistent with the recommendation of the Crop Advisory Committee for Pecans and Hickories [Grauke, 1985, HortScience 20(4):629-630.]. At the time that recommendation was made, a proposal to conserve the name of pecan as Carya illinoensis (Wangenheim) K. Koch was submitted to the Standing Committee for Stabilization of Nomenclature, for consideration at the meeting at the XIVth International Botanical Congress in Berlin, July 1987 (Grauke et al., 1987, Taxon 35:174-177). We were confident that the proposal would be accepted, given the long history of that name's usage and the fact that previous Botanical Congresses, although lacking a mechanism for authoritative implementation, had decided in favor of C. illinoensis (Schubert, 1969, Regime Veg. 60:110). Unfortunately, the proposal was rejected (Nicolson, 1988, Taxon 37:440). As a result, the appropriate scientific name of pecan is
Carya illinoinensis (Wangenh.) K. Koch.

L. J. Grauke,
U.S. Dept. of Agriculture
Pecan Breeding & Genetics
Somerville, TX"

His summary information about Carya illinoinensis can be found at this link.

Photo taken from the A&M site linked above.

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