Californian White Oak, Valley oak

Quercus lobata

Physical Characteristics

Quercus lobata is a deciduous Tree growing to 30 m (98ft 5in) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 7 and is not frost tender. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and is pollinated by Wind. Suitable for: medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil. The plant can tolerates strong winds but not maritime exposure.

Distribution

South-western N. America - California.

Habitats

Woodland Garden Canopy;

Edible Uses

Edible Parts: Seed Edible Uses: Coffee Seed - cooked[257]. A staple food for several native North American Indian tribes[257]. Quite large, it is up to 5cm long and 15mm wide[82, 200]. The seed of this species is sweet and low in tannin and needs little if any leeching[183, 229]. Any bitter tannins can be leached out by thoroughly washing the dried and ground up seed in water, though many minerals will also be lost. 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 seed can be roasted and then eaten, its taste is something like a cross between sunflower seeds and popcorn[183]. The seed can also be ground into a powder and used in making bread etc[183]. Roasted seed is a coffee substitute.

Medicinal Uses

Astringent Dysentery Poultice Salve Any galls produced on the tree are strongly astringent and can be used in the treatment of haemorrhages, chronic diarrhoea, dysentery etc[4]. A poultice of the ground galls and salt has been used as a treatment for burns, sores and cuts[257]. A decoction of the bark has been used as a cough medicine and a treatment for diarrhoea[257]. The pulverized bark has been used as a dusting powder to dry up running sores, it is particularly useful for babies with sore umbilicus[257].

Known Hazards

None known