Fruit Tree
Western Schley Pecan
Carya illinoinensis 'Western Schley' · Juglandaceae
Also called: Western Pecan, 'Western' Pecan, Schley Pecan (Western strain)
Western Schley Pecan (Carya illinoinensis 'Western Schley') is a high-water fruit tree well suited to Tucson and the low desert. It thrives in full sun.
Western Schley Pecan at a glance
- Water use
- High (established)
- Sun
- Full sun; needs a large open area with no overhead competition.
- Mature size
- Very large: 40-70 ft tall and 40-50 ft wide; needs roughly 30-40 ft spacing.
- Growth rate
- Moderate to fast (with adequate water)
- Bloom
- Greenish-yellow catkins (inconspicuous), Catkins (pollen) and small female flowers in spring; nuts mature and harvest in late fall (November).
- Cold hardiness
- Fully cold-hardy in Tucson (well below 0 F when dormant); no frost protection needed.
- Soil
- Prefers deep, well-drained soil; struggles in shallow caliche. Best in deep alluvial soils like those of the Santa Cruz / Sahuarita valley. Alkalinity induces zinc and iron chlorosis.
- Native range
- Species native to the south-central U.S. and northern Mexico (Mississippi River valley, Texas). Not native to the Sonoran Desert; widely grown commercially around Tucson/Sahuarita.
- Best used as
- Edible nuts, Large shade tree, Commercial orchard / agritourism
- Wildlife
- Nuts feed birds, squirrels, and other wildlife.
- Toxicity
- Nuts are edible and non-toxic. As with other Juglandaceae, hulls/leaves contain juglone-type compounds; pecan is far less juglone-toxic than black walnut. Tree nut allergen for sensitive people.
How to grow Western Schley Pecan in Tucson & the low desert
Watering
Very high water demand and the limiting factor in Tucson. Mature trees need deep flood-style or long drip irrigation every 7-10 days through the hot season, soaking the entire root zone; inadequate water causes poor nut fill and 'pops'. Not a low-water-use tree.
Fertilizer & nutrients
Heavy nitrogen feeder; apply nitrogen in split applications spring through early summer. Tucson's alkaline soils cause zinc deficiency, so foliar zinc sprays (zinc sulfate) in spring as leaves expand are essential for good growth and nut fill.
Pruning & care
Prune in winter dormancy to develop a central leader and strong scaffolds; minimal pruning once mature beyond removing deadwood. Avoid topping.
Notes
'Western Schley' ('Western') is THE workhorse pecan of southern Arizona and the dominant commercial cultivar around Tucson/Sahuarita. It is partially self-fruitful but yields best with a pollinizer (e.g., 'Wichita'). Reserve for large lots only and budget for high water plus annual zinc treatment; not appropriate for water-conserving xeriscapes.
Sources: University of Arizona Cooperative Extension (Pecan production guides); Pima County Master Gardeners; USDA / NMSU pecan culture references