Japanese Emperor Oak
Herb: Japanese Emperor Oak
Latin name: Quercus dentata
Synonyms: Quercus daimio
Family: Fagaceae (Beech Family)
Medicinal use of Japanese Emperor Oak:Any galls produced on the tree are strongly astringent and can be used in the treatment of haemorrhages, chronic diarrhoea, dysentery etc.
Description of the plant:
Habitat of the herb:Sunny slopes and thickets in lowland and mountains all over Japan. Mixed mesophytic forests below 100 - 2700 metres.
Edible parts of Japanese Emperor Oak:Seed - cooked. The seed is up to 23mm long and 15mm wide. Rich in starch. 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 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 the herb: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. Tannin is obtained from the bark.
Propagation of Japanese Emperor Oak:Seed - it quickly loses viability if it is allowed to dry out. It can be stored moist and cool overwinter but is best sown as soon as it is ripe in an outdoor seed bed, though it must be protected from mice, squirrels etc. Small quantities of seed can be sown in deep pots in a cold frame. Plants produce a deep taproot and need to be planted out into their permanent positions as soon as possible, in fact seed sown in situ will produce the best trees. Trees should not be left in a nursery bed for more than 2 growing seasons without being moved or they will transplant very badly.
Cultivation of the herb:Sunny slopes and thickets in lowland and mountains all over Japan. Mixed mesophytic forests below 100 - 2700 metres.
Known hazards of Quercus dentata:None known
Plant information taken from the Plants For A Future.