Japanese Emperor Oak, Daimyo oak
Quercus dentata
Family: Fagaceae
What it is like
Quercus dentata is a deciduous Tree growing to 20 m (65ft) by 12 m (39ft) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 5 and is not frost tender. It is in flower from April to May, and the seeds ripen from October to November. 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 and neutral 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.
Height (m): 20
Where it is found
Sunny slopes and thickets in lowland and mountains all over Japan. Mixed mesophytic forests below 100 - 2700 metres.
E. Asia - China, Japan, Korea.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 2
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.
Seed: includes nuts, cereals, peas and beans.
Coffee: the various substitutes that can be used instead of coffee.
Medicine
Rating: 2
Any galls produced on the tree are strongly astringent and can be used in the treatment of haemorrhages, chronic diarrhoea, dysentery etc.
Astringent: Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.
Dysentery: Used in treating dysentery - an infection of the intestines that causes diarrhoea containing blood or mucus.
Other
Rating: 2
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.
Repellent: Plants that are said to deter but not necessarily kill various mammals, birds, insects etc.
Tannin: An astringent substance obtaied from plants, it is used medicinally, as a dye and mordant, stabilizer in pesticide etc.
Wood: A list of the trees and shrubs that are noted for having useful wood.
How it is grown
Prefers a good deep fertile loam which can be on the stiff side. Prefers an acid soil. Young plants tolerate reasonable levels of side shade. Tolerates moderate exposure, surviving well but being somewhat stunted. Trees are fast growing, but they prefer warmer summers than are usually experienced in Britain and often grow poorly in this country, failing to properly ripen their wood which results in frost damage overwinter. Intolerant of root disturbance, trees should be planted in their permanent positions whilst young. The seed ripens in its first year. Hybridizes freely with other members of the genus. Plants in this genus are notably resistant to honey fungus.
Propagating it: 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.
Best place to grow: Woodland Garden Canopy;
Habit: Tree
Hardiness: 4-8
Growth: Fast
Soil: Medium, heavy (clay)
Shade: Semi-shade, no shade
Moisture: Moist
Things to keep in mind
Its other names
Local names
Synonyms
Q. daimio.