Castanea sativa

A deciduous tree reaching 30m tall and 15m wide at a medium growth rate, hardy to UK zone 5. Flowers appear in July with seeds ripening by October. Monoecious and bee-pollinated. Attracts wildlife. Tolerates light sandy, medium loamy, and heavy clay soils; prefers well-drained conditions but grows in poor soils. Adapts to mildly acid, neutral, and very acid pH. Requires full sun, tolerates both dry and moist soil, and can withstand drought and maritime exposure.

Description

A large deciduous tree up to 30-40 m high. It spreads to 6-15 m across. The stem is erect and stout. It has spreading branches and a wide rounded crown. The bark is grey-brown. The bark is ridged in a right handed spiral. The large leaves have toothed edges. The leaves are oblong to sword shaped and have prominent veins. The leaves can be 20 cm long. Leaves turn yellow to brown in autumn. Male and female flowers are separate. The male flowers are brownish and hang down like a cat's tail. They are 20 cm long. The female flowers are joined together into a distinctive little tube. Normally male flowers are lower in the current season's shoots while the female (or both sexes) flowers are nearer the end of the shoot. The pollen can have an unpleasant smell. The brown nuts are inside green, spiny coverings. These burrs open to reveal the nut. The outer shell is shiny light brown. It needs to be cut off with a sharp knife. A softer layer appears inside surrounding the nut.

Edible Uses

The seeds can be eaten raw or cooked, though they have a somewhat astringent flavour raw. Baking greatly improves them — the texture becomes floury and the flavour resembles sweet potato. The seeds are rich in carbohydrates and can be dried and ground into a flour for use in breads, puddings, and as a soup thickener. The roasted seed works as a coffee substitute, and a sugar can also be extracted from the seed.

Traditional Uses

The kernel of the nuts is eaten boiled or roasted. They are also slowly dried then ground and made into porridge. The flour can be used for breads, puddings or used to thicken soups. The roasted seeds are used as a coffee substitute. Sugar can be extracted from the nuts.

Medicinal Uses

Sweet chestnut leaves and bark are a good source of tannins, which provide an astringent action useful for treating bleeding and diarrhoea. The leaves and bark are anti-inflammatory, astringent, expectorant, and tonic. They are harvested in June or July and can be used fresh or dried. An infusion has been used to treat fevers and ague, and is particularly valued for relieving convulsive coughs such as whooping cough and other irritable conditions of the respiratory system. The leaves can also be applied in the treatment of rheumatism, lower back pain, and stiff muscles and joints. A decoction makes a useful gargle for sore throats. The plant is used in Bach flower remedies, with the prescribing keywords being 'Extreme mental anguish', 'Hopelessness', and 'Despair'.

Distribution

A Mediterranean climate plant. It can withstand frost. Trees do produce in the highlands of South India so may produce in the highlands of PNG. It requires light to medium, well drained soils. It is drought tender. It is slightly hardier than a peach and has less chilling requirement than a walnut. It is not suited to heat or humidity. In Indonesia it is planted above 1,400 m above sea level. It suits hardiness zones 5-9. Arboretum Tasmania. Hobart Botanical Gardens.

Where It Grows

Africa, Albania, Algeria, Andorra, Armenia, Asia, Australia, Austria, Azerbaijan, Balkans, Bosnia, Brazil, Britain, Bulgaria, Caucasus, Chile, China, Colombia, Cuba, East Africa, Europe*, Falklands, France, Georgia, Greece, Haiti, Himalayas, Hungary, India, Indonesia, Iran, Italy, Jamaica, Japan, Macedonia, Mediterranean, Madagascar, Mediterranean, Mexico, Middle East, Morocco, Myanmar, Netherlands, North Africa, North America, Pacific, Pakistan, Papua New Guinea, PNG, Portugal, Russia, San Marino, SE Asia, Serbia, Sicily, Slovenia, South America, Spain, Switzerland, Tasmania, Tunisia, Turkey, Türkiye, USA, West Indies, Yugoslavia,

Cultivation

Prefers a good well-drained slightly acid loam in a sunny position but it also succeeds in dry soils. Once established, it is very drought tolerant. Plants are very tolerant of highly acid, infertile dry sands. Averse to calcareous soils but succeeds on harder limestones. Tolerates maritime exposure though it is slower growing in such a position. The dormant plant is very cold-hardy in Britain, though the young growth in spring, even on mature plants, is frost-tender. The sweet chestnut is often cultivated for its edible seed in warm temperate zones, there are several named varieties. Both 'Marron de Lyon' and 'Paragon' produce fruits with a single large kernel (rather than 2 - 4 smaller kernels) and so are preferred for commercial production. Castanea sativa x crenata: The hybrid sweet chestnut ‘Marigoule’ is a good choice If you only want to grow one tree as Marigoule is a partly self-fertile cultivar. Sweet chestnuts require a warm dry summer in order to ripen their fruit properly in Britain and even then these seeds are generally inferior in size and quality to seeds grown in continental climates. Most species in this genus are not very well adapted for the cooler maritime climate of Britain, preferring hotter summers, but this species grows well here. An excellent soil-enriching understorey in pine forests. Flowers are produced on wood of the current year's growth and they are very attractive to bees.. Plants are fairly self-sterile. They hybridize freely with other members of this genus. At one time this tree was widely grown in coppiced woodlands for its wood, but the practise of coppicing has fallen into virtual disuse. Trees regrow very quickly after being cut down, producing utilizable timber every 10 years. This species is not often seen in Cornwall though it grows very well there. Trees take 30 years from seed to come into bearing. Plants in this genus are notably resistant to honey fungus. In garden design, as well as the above-ground architecture of a plant, root structure considerations help in choosing plants that work together for their optimal soil requirements including nutrients and water. Thick or swollen - fibrous or tap root.

Propagation

Sow seed as soon as it is ripe, either in a cold frame or in an outdoor seedbed, and protect it from mice and squirrels. The seed has short viability and must not be allowed to dry out. It can be stored moist in a cool place such as the salad compartment of a fridge for a few months, but should be checked regularly for signs of germination. Germination typically occurs in late winter or early spring. Seedlings raised outdoors can be left in situ for one to two years before being moved to permanent positions. Plants grown in pots can go out to permanent positions in summer or autumn, with some cold protection in their first winter.

Other Uses

Tannin is obtained from the bark; the wood, leaves, and seed husks also contain tannin. The husks contain 10–13% tannin; on a 10% moisture basis, the bark contains 6.8% tannin and the wood 13.4%. Ground seed has been used as a source of starch and for whitening linen cloth. A hair shampoo made from the leaves and fruit skins imparts a golden sheen to the hair. The wood is hard, strong, and light; young growth is very durable, though older wood becomes brittle and prone to cracking. It is used for carpentry, turnery, props, basketry, and fence posts, and makes excellent fuel.

Production

This is the fastest growing of the chestnuts. Trees can live for centuries. Seedling trees can bear after 3-10 years. Up to 100 kg of nuts can be produced per year. There is little seasonal fluctuation in nut production. The nuts fall naturally. The nuts need to be partly dried to improve the taste and stop rots. The nuts can be stored in closed boxes, with newspaper to absorb the moisture. If kept cool they will store for 6 months. Kernels can be kept for much longer if cooked and frozen. To do this the nut is placed in boiling water for 2 minutes then peeled and cooled and frozen.

Other Information

Seeds have been introduced into Papua New Guinea for growing trials only. It is commonly used in Europe. It is cultivated. It is sold in local markets.

Notes

All Castanea bear edible nuts. There are about 12 Castanea species.

Dangerous Lookalikes

This plant can be confused with the following toxic species. Always verify identification carefully before consuming any wild plant.

VERY TOXIC

Horse Chestnut (Conker)

Aesculus hippocastanum

Solipsist

Safe

European Chestnut

Castanea sativa

(c) Li Jianong, some rights reserved (CC BY-NC), uploaded by Li Jianong

Horse Chestnut (Conker): Round smooth nuts (conkers), bumpy green husk (not very spiny), palmate compound leaves (like a hand).

European Chestnut: Nuts with pointed tassel, very spiny bur casing, simple toothed leaves.

Nutrition

Synonyms

Also Known As

Castagno, Castana, Castano, Chastanhes, Chataignier, Edelkastanie, ErbuGastana, Geszkenye, Geskonye, Italian chestnut, Kapoo, Khanor, Kosten, Mitha, Pravi kostanj, Shaganak, Szelidgesztenye, Thit-e, Ts'abli, Tzabli, Yadliv kesten

References (83)

• Ambasta S.P. (Ed.), 2000, The Useful Plants of India. CSIR India. p 110
• Barreau, A., et al, 2016, How Can We Teach Our Children if We Cannot Access the Forest? Generational Change in Mapuche Knowledge of Wild Edible Plants in Andean Temperate Ecosystems of Chile. Journal of Ethnobiology 36(2): 412–432
• Bianchini, F., Corbetta, F., and Pistoia, M., 1975, Fruits of the Earth. Cassell. p 190
• Blamey, M and Grey-Wilson, C., 2005, Wild flowers of the Mediterranean. A & C Black London. p 31
• Bodkin, F., 1991, Encyclopedia Botanica. Cornstalk publishing, p 224

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