By David Wall, Mount Pleasant Master Gardener
Mexican white oak (Quercus polymorpha) or its alias as Monterrey oak is incredible tree that remains to date relatively unknown. A primary reason is that until 1992 when a small stand was discovered in SW TX, it was not known to exist in the U.S. Normal range is from Guatemala through Mexico. Since 1992, it has become adapted to hardiness zones 7-10, and is considered a highly desirable tree.
Mexican white oak (MWO) is an exception to the rule that fast-growing trees are trash trees. They grow to roughly 40’ but quickly get there, growing up to 4’ a year in good soil and climate. They start out thin and gangly but fill out to 2’ in diameter. Lifespan is roughly 100 years. Limbs and leaves provide a broad, thick and rounded foliage.
MWO leaves are atypical oak, as there are no definitive lobes. They’re four to five inches long and can have smooth or serrated edges. Different trees can have can have different leaf shapes. Leaves are often serrated when the tree is very small, becoming smoother as the tree matures. They may start out with a reddish-peach color before turning bright green and finishing as a deep green color.
Like live oaks, MWOs hold onto their leaves until late winter or early spring. Immediately after defoliation, re-foliation proceeds very fast, with bare limbs only existing for 2-8 weeks depending on the hardiness zone.
MWOs do well in wet-dry areas and river banks-mountainous areas and are considered very healthy. They’re very drought tolerant, and triple digit temperatures don’t slow them down. While they prefer neutral to alkaline sols, they do well in many different soil types.
Prune lower limbs to raise the canopy. Otherwise, little care is required. Google nurseries for MWOs in stock. If none local, keep searching!