It is occasionally known as Blue oak , mountain oak , mountain white oak and iron oak.
Blue Oaks are medium-sized deciduous trees growing up to 50-82 feet tall, usually with a somewhat irregularly-shaped crown, and a trunk 1.5-3 feet in diameter. The tallest recorded oak was found in southern Alameda County, at 94 feet.
The bark is light gray with many medium-sized dark cracks; from a distance, it can appear almost white. The name Blue Oak derives from the dark blue-green tint of its leaves, which are deciduous, 1.5-4 inches long, and entire or shallowly lobed and turn a yellow orange color in the autumn. .The blue color can be subtle but becomes much more evident when viewed next to one of the live oaks with whom it shares its range, which tend to have much greener leaves.
The acorns are around an inch long, often with a narrowed base, with a moderately sweet kernel, and mature in 6-7 months from pollination.
Native to the dry woodlands and valleys around the California's Central Valley and the interior valleys of southern California.
Hardy to USDA Zone 8?
Medicinal use of :
Any galls produced on the tree are strongly astringent and can be used in the treatment of hemorrhages, chronic diarrhea, dysentery etc. A poultice of the ground galls and salt has been used in the treatment of burns, sores and cuts. It has also been used as a wash for sore eyes. The leaves have been chewed as a treatment for sore throats.
Edible parts of :
Seed - cooked. The seed has been used as a staple food by some native North American Indian tribes. Somewhat sweet. A good size, to 25mm long and wide. It can be dried, ground into a powder and used as a thickening in stews etc or mixed with cereals for making bread. The seed from some trees contains bitter tannins, these can be leached out by thoroughly washing the seed in running water though many minerals will also be lost. Either the whole seed can be used or the seed can be dried and ground it into a powder. It can take several days or even weeks to properly leach whole seeds, one method was to wrap them in a cloth bag and place them in a stream. Leaching the powder is quicker. A simple taste test can tell when the tannin has been leached. The traditional method of preparing the seed was to bury it in boggy ground overwinter. The germinating seed was dug up in the spring when it would have lost most of its astringency. The roasted seed is a coffee substitute.
Other uses of :
A mulch of the leaves repels slugs, grubs etc, though fresh leaves should not be used as these can inhibit plant growth. Oak galls are excrescences that are sometimes produced in great numbers on the tree and are caused by the activity of the larvae of different insects. The insects live inside these galls, obtaining their nutrient therein. When the insect pupates and leaves, the gall can be used as a rich source of tannin, that can also be used as a dyestuff. The branches have been used to make rims for twined work baskets. The acorn meal has been used to mend cracks in clay pots. The seed cups are used as buttons. Wood - hard, heavy, strong, brittle. It has a strong cross-grain and is difficult to split. Of little commercial value, it is used mainly for fuel.