Gray Oak
Quercus grisea
Family: Fagaceae
OTHER NAMES
Spanish: encino azul, encino blanco
CHARACTERISTICS
Evergreen trees averaging about 15-30’ tall with thick leaves and a grayish cast. Flowers in spring, followed by acorns that ripen in the fall and may persist in the tree (not falling) until new leaves are produced—which can be the following spring or even early summer.
LANDSCAPE USE
Medium-sized shade tree.
Photo of some younger trees by Eric Hough, iNaturalist
Quercus grisea on SEINET
GROWING CONDITIONS
AN EXPLANAITION OF TERMS USED
SUN afternoon shade encouraged for young plants in the low desert, older plants can take sun, full to part sun in upper elevations
WATER moderate
SOIL prefers good drainage and amendments encouraged
HARDINESS hardy to about 0°F
BASIN middle zone
CONTAINER does ok in container but will not attain full size
NUTRITION moderate
MAINTENANCE very little
ECOLOGY
Flowers in spring with inconspicuous, wind-pollinated flowers. Acorns ripen in fall. Oaks are wildlife keystone species hosting a mind-boggling number of insects. This brings in a vast array of substrate-insectivorous birds (birds that spend their time on these trees eating the insects). The acorns are important food for many birds and mammals (and some species eaten by people). The trees also provide important habitat for many birds and mammals. Almost all the oaks host a multitude of moths and butterflies including the following species:
Mexican-M Hairstreak (Parrhasius moctezuma)
Arizona Sister (Adelpha eulalia)
Short-tailed Skipper (Zestusa dorus)
Arizona Dull Firetip (Apyrrothrix araxes ssp. arizonae)
Burgess’s Sleepy Duskywing (Erynnis brizo ssp. burgessi)
Clitus Duskywing (Erynnis juvenalis ssp. clitus)
Meridian duskywing (Erynnis meridianus ssp. meridianus)
Scudder's Duskywing (Erynnis scudderi)
Mournful Duskywing (Erynnis tristis)
Oaks also host a diversity of insects that cause growths called “galls”. Galls are protective nests for the larvae of various insects (mostly tiny stingless wasps) to develop protected from pests. The have a diversity of shapes from giant ball-like growths, to small growths, on leaves or young stems. These galls do not harm healthy trees. Emory oaks that grow in riparian zones and get really tall are a favorite nesting site for owls and other raptors.
Oaks attract numerous other insects which, in turn, attracts canopy-gleaning birds.
ETHNOBOTANY
This is one of the more edible acorn-producing oaks—similar to belota or emory oak (Quercus emoryi). Gray oak is much faster-growing than the emory oak which makes it a promising crop for acorn production. It is also used as fence posts and firewood. Large-sized gray oak are sometimes used for furniture.
NATURAL DISTRIBUTION
Found in riparian and montane forests, woodlands, and savannah from 3,500-7,000’ in Arizona, Colorado, New Mexico, Texas, south into central Mexico.
TAXONOMY AND NAME
This plant is in the family Fagaceae, the beech family. There are 627 accepted species in the genus Quercus widely distributed in the northern hemisphere.
The genus "Quercus" is from Latin, meaning "oak", and “grisea” means gray.