Quercus suber occidentalis
| Quercus suber | |
| Light: |   |
| Moisture: |   |
| Hardiness: | 8 |
| Soil pH: | 5.6-8.4 |
| Evergreen | |
| Height: | 59' |
| Width: | 43' |
| Speed: | Slow |
| Blooms: | Late Spring-Early Summer |
| Open Woods Forest | |
| Native to: | |
| Edible Rating: |  |
| Medicinal Rating: |  |
| Tea: | Yes |
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Quercus suber occidentalis (common name: cork oak)
Propagation: 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[1]. 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: Prefers a good deep fertile loam which can be on the stiff side[1]. Lime tolerant[2]. Young plants tolerate reasonable levels of side shade[3]. Tolerates moderate exposure, surviving well but being somewhat stunted[3].
Cultivated for its bark in Europe, it is the main source of cork[4][5]. This sub-species has slightly thinner bark than the species[1].Trees are first harvested when they are 25 - 30 years old and are then harvested on a 10 - 12 year rotation.
Only hardy in the milder areas of Britain[3], it is not very frost resistant[6]. This sub-species is somewhat hardier than the type[1]. Trees grow well in Cornwall where there are many large specimens[1][7][8]. There is at least one large healthy specimen of this tree at Kew, it produced some seeds in the hot summer of 1989[K].
Transplants badly unless it is moved regularly, it should only be moved in September or as growth commences in late spring[1].
Does not fruit well in Britain.
Most of the trees grown in Britain as Q. suber are in fact this sub-species[1].
Hybridizes freely with other members of the genus[3].
This species is notably resistant to honey fungus[9][3].
Range: S. Europe to N. Africa.
Habitat: Siliceous hills on the littoral[5].
Edibility: Seed - cooked[10]. A famine food[11]. 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.
Medicinal: Any galls produced on the tree are strongly astringent and can be used in the treatment of haemorrhages, chronic diarrhoea, dysentery etc[12].
Usage: 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[12].
Bark is the source of cork, it is much used for heat and sound insulation, flooring, floats etc. Trees are first harvested when they are 25 - 30 years old[13], and then harvested every 6 - 12 years[14]. The bark must be removed carefully so as not to harm the tree. A large tree can yield up to 1 tonne of cork.
Wood.
Pollinators: Wind
Soil: Can grow in medium and heavy soils.
Wind: Tolerates strong winds
In Leaf: Evergreen
Seed Ripens: Mid Fall
Flower Type: Monoecious
Heavy Clay: Grows in heavy-clay soils.
Also Known As: Q. occidentalis.
Links
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Bean, William. Trees and Shrubs Hardy in Great Britain. Murray, 1981.
- ↑ Brickell, Christopher. The RHS Gardener's Encyclopedia of Plants and Flowers. Dorling Kindersley Publishers, 1990.
- ↑ 3.0 3.1 3.2 3.3 3.4 Huxley, Anthony. The New Royal Horticultural Society Dictionary of Gardening. MacMillan Press, 1992.
- ↑ Tutin, Tom et al.. Flora Europaea. Cambridge University Press, 1964.
- ↑ 5.0 5.1 Polunin, Oleg. Flowers of the Mediterranean. Hogarth Press, 1987.
- ↑ Gordon, A and D Rowe. Seed Manual for Ornamental Trees and Shrubs. 1982.
- ↑ Arnold-Forster, William. Shrubs for the Milder Counties.
- ↑ Thurston, Edgar. Trees and Shrubs in Cornwall. Cambridge University Press, 1930.
- ↑ RHS. The Garden Volume 112. Royal Horticultural Society, 1987.
- ↑ Tanaka, Tyōzaburō. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing, 1976.
- ↑ Kunkel, Günther. Plants for Human Consumption. Koeltz Scientific Books, 1984.
- ↑ 12.0 12.1 Grieve, Margaret. A Modern Herbal. Penguin, 1984.
- ↑ Komarov, Vladimir. Flora of the USSR. Gantner Verlag, 1968.
- ↑ Rosengarten Jr., Frederic. The Book of Edible Nuts. Dover, 1984.