Arizona White Oak
Quercus arizonica
Family: Fagaceae
CHARACTERISTICS
Evergreen trees (will lose leaves in extreme cold found at higher elevations), growing up to about 50’ tall in ideal conditions, often much smaller, especially in the low desert. Many “evergreen” oaks will look very brown before the new foliage emerges in late spring/early summer.
LANDSCAPE USE
Small landscape tree.
GROWING CONDITIONS
AN EXPLANAITION OF TERMS USED
SUN afternoon shade recommended for young trees in the low desert, older trees can take more sun. Full to part sun for upper elevations
WATER moderate
SOIL prefers sandy or rocky soil, amendments encouraged
HARDINESS hardy to about 5°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.
Oaks attract numerous other insects which, in turn, attracts canopy-gleaning birds.
ETHNOBOTANY
Sonoran Scrub Oak is used for food, tools and other purposes by southwestern United States indigenous peoples. The acorns need a considerable amount of treatment before they are edible.
NATURAL DISTRIBUTION
Found in oak and piñon woodlands, particularly along canyons from 4,000-8,000’ mostly in Arizona, New Mexico, and south into northern 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.
Quercus is the classical Latin word for oak, thought to be derived from Celtic quer, fine, and cuez, tree, while arizonica means of or from Arizona.
Arizona white oak is called such because the trunk has a general light color, with very rough bark, quite distinctive from most other native oaks. Photo by mmao, iNaturalist
Young green acorns of white oak, photo by Ken Kertell, iNaturalist
The foliage has a slightly rough texture. Photo. by CK Kelly, iNaturalist
Many oak galls can look like fruit, which can confuse someone trying to identify a plant. These galls are caused by tiny waps called gall wasps. Photo by wildfloweraz, iNaturalist
Some galls are hairy, photo by Peter, iNaturalist
The tassel-like flowers occur in spring, photo by er-birds, iNaturalist