HORSE CHESTNUT: CHARACTERISTICS, HABITAT, CULTIVATION, CARE - BIOLOGY - 2025

The horse chestnut (Aesculus hippocastanum) is a tall shrub species belonging to the Sapindaceae family. Known as Indian chestnut, crazy chestnut or false chestnut is an exotic tree native to the Caucasus and the Balkan Peninsula.

Today it is a cosmopolitan species cultivated as an ornamental for its particular beauty and resistance to various environmental conditions. It is common in humid mountain forests in temperate climates on clay or sandy soils.

Horse chestnut (Aesculus hippocastanum). Source: pixabay.com

It is a 25-30 m tall tree with smooth bark when young, rough and rough when adult, with a dense, globose crown. The dark green webbed leaves are distributed along extensive fragile and undulating branches.

Its white and very fragrant flowers are grouped in conical or pyramidal inflorescences. The fruit is an equine capsule inside which the brown seeds or chestnuts are located.

Its main use is as an ornamental, the low weight and fragile wood has little commercial use, although it is used to make handicrafts. This constitutes the main reason that many specimens survive for years, finding trees more than 3 m thick.

On the other hand, it contains various active principles such as the glucoside esculin and the phlebotonic escin. These substances allow the blood to circulate normally, helping to prevent the formation of varicose veins and reduce the discomfort caused by varicose veins and hemorrhoids.

General characteristics

Appearance

- Species: Aesculus hippocastanum L., Sp. Pl., Vol. 1 p. 344, 1753

Etymology

- Aesculus: the generic name comes from the old Latin «aesculus, -i» in reference to the fruit similar to an acorn with hard skin and its firm and yellowish pulp.

- hippocastanum: the specific adjective derives from the Greek «ίπποχ, hippos» which means horse and from the Latin «castanea», which means chestnut. It is literally translated as "horse chestnut" in reference to a Turkish legend that tells how the chestnut calms asthma and horse coughs.

Habitat and distribution

It is native to the Caucasus and the Balkans, and wild in northern India, Asia Minor, and the Himalayas. At present it has been introduced in various temperate regions around the world, mainly in northern Europe and North America.

Horse chestnut leaves (Aesculus hippocastanum). Source: Димитър Найденов / Dimìtar Nàydenov

In Europe it was introduced during the 16th century, in the United Kingdom in the middle of the 17th century and was brought to North America by settlers. Today it is considered an introduced species in Germany, Denmark, Spain, France, Finland, Norway, Portugal, Sweden, Switzerland and Great Britain.

In Great Britain it is found particularly in all regions, with the exception of the Grampian Mountains in Scotland and to the northeast of the islands. It can be found in gardens, squares and farms, as well as diverse habitats from mixed, humid and deciduous forests to swamps.

It naturally develops in various habitats, alone or in association with oak, maples, alders or walnut trees. It grows practically on any type of well-drained and slightly acidic soil up to altitude levels of 1,500 meters above sea level.

Culture

The horse chestnut is propagated through fresh, viable seeds that must be sown during the fall. Indeed, the seeds tend to dehydrate quickly so they must be stored at a low temperature once collected.

The sowing is established in polyethylene bags with a fertile substrate with high sand content that favors good drainage. It is recommended to sow during the cold months (autumn-winter), so that the humid environment of spring promotes germination.

One of the techniques consists of sowing directly with seeds collected from the plant or its surroundings. We try to maintain good lighting conditions, temperature, humidity and control of pests, diseases or weeds until the appearance of the seedlings.

Once seedlings of 25-30 cm in height have been obtained, the most vigorous ones are selected to be transplanted in the definitive place of cultivation. Another technique consists of keeping the seeds under clean and fresh water for several days until the appearance of rootlets.

Tender fruit of horse chestnut (Aesculus hippocastanum). Source: pixabay.com

Once they are rooted, they proceed to sow under the same conditions of the first method, then selecting the best-developed seedlings for transplantation. For its effective development, fertile, loose and humid soils are required, it tolerates soils of limestone origin as long as they are well drained.

Solar radiation is essential to ensure the rapid growth of horse chestnut specimens. A closed shading tends to drastically reduce the growth rate, which influences the flowering and fruiting processes.

Likewise, the nutritional condition of the land is essential to promote flowering and subsequent fruiting. To meet the nutritional requirements, it is recommended to apply composted organic fertilizers or commercial fertilizer formulas.

Fertilizers with high nitrogen content promote foliar development. On the other hand, phosphorus is necessary for excellent flowering. Likewise, the application of potassium gives the plant strength to resist the incidence of different pests or diseases.

Care

Location

Horse chestnut should be established outdoors and outdoors, if possible in places where it receives solar radiation all day. In Mediterranean environments it can be sown in a shady place, as long as it receives a higher percentage of solar radiation than shade.

This species is typical of temperate zones, so it tolerates freezing conditions with occasional frosts below 17 ºC. However, it is susceptible to temperature ranges above 35ºC.

Floor

It adapts to fertile, loamy soils with good drainage capacity of slightly acidic pH, with values ​​of 6-6.5. Although it can grow on alkaline soils, that is, a pH higher than 7, it is conditioned to adequate drainage.

Irrigation

During the warm months the plant requires frequent watering with rain or acidified water, as it does not tolerate drought. Indeed, it requires 3-4 waterings per week, especially when the environmental conditions are very hot and dry. In cool months, waterings can be spaced 2-3 times a week.

Fertilization

In the juvenile phase it is recommended to apply organic fertilizers that stimulate its growth and development. Adult plants do not require frequent watering, but it is advisable to apply commercial formulas after pruning and before the flowering process.

Flowering horse chestnut tree. Source: AnRo0002

Pruning

This tree does not require frequent pruning although it is advisable to carry out sanitation pruning when dry branches or with symptoms of disease are observed. Only in case of disproportionate growth of the branches, maintenance pruning is advisable.

Plagues and diseases

The horse chestnut is a resistant plant that, grown under suitable agroclimatic conditions, is little attacked by pests or diseases. However, in certain environmental conditions it can suffer the incidence of certain pathogens.

Among the pests with the highest incidence we can mention the white soil worm, mealybug, defoliator caterpillar or spider mite. Of the diseases, the fungus Guignardia aesculi causal agent of the disease called leaf spot.

The white soil worm is the larva of certain coleopterans, they appear during the establishment phase attacking the roots or the base of the stem. The control is carried out in a biological way by applying the Bacillus thuriengensis bacteria to the soil.

The mealybug is a hemipteran insect that causes damage at the apical or foliar shoot level. Low incidents are controlled by physical methods, severe attacks are controlled with applications of chlorpyrifos plus paraffin oil.

The incidence of spider mite causes damage to the leaves, its control is carried out with Neem oil or applications of acaricides. The defoliating caterpillars consume the leaves causing the reduction of the foliar area which affects the light uptake and indirectly the yield.

The phytopathogenic fungus Guignardia aesculi that causes leaf spot causes large brown spots on the leaf surface. The plant is usually contaminated during pruning by using contaminated implements. Control is done with systemic fungicides.

Horse chestnut trunk (Aesculus hippocastanum). Source: AnRo0002

Applications

Industrial

Compounds used in the cosmetic industry such as shampoo for dark hair and various products for hair use are extracted from the bark. In addition, tannins used for the preparation of tinctures used in homeopathic therapies are obtained from the bark.

The crushed and ground seeds are used for the production of fodder intended as a nutritional supplement for livestock. In the British Isles the seeds are used to make handcrafted toys.

Medicinal

From the Aesculus hippocastanum species, the leaves, bark and seeds are used in herbal medicine. In general, it is used to reduce fever, heal local edema, regulate circulation, calm disorders of the nervous system and alleviate hemorrhoids and phlebitis problems.

Indeed, this tree contains esculin and escin, which are two active principles that prevent the formation of edema. In addition, it gives resistance to the blood vessels which allows to alleviate problems such as inflamed veins, varicose veins and hemorrhoids.

Applied topically as an ointment, it relieves inflammation caused by venous insufficiencies, phlebitis, varicose veins and other circulatory problems such as edema and ecchymosis. Consumed orally as a capsule made from a dry extract, it allows control of capillary fragility, dysmenorrhea, metrorrhagia and epistaxis.

Ornamental

One of its main uses is as an ornamental plant, either growing isolated specimens, in rows or in association with other species.

Contraindications

Horse chestnut seeds contain highly toxic elements. For this reason, it is important to know that, although the seeds are not dangerous to contact, they should not be consumed since they are slightly toxic.

References

1. Aesculus hippocastanum. (2019). Wikipedia, The Free Encyclopedia. Recovered at: es.wikipedia.org
2. Aesculus hippocastanum L. (2019) Asturnatura. ISSN: 1887-8068. Recovered at: asturnatura.com
3. Horse chestnut. Aesculus hippocastanum (2019) Herbwisdom RFI Media Ltd. Retrieved at: herbwisdom.com
4. Delporte Vergara, Clara (2010) Castaño de Indias. Natural products. University of Chile.
5. Ravazzi, C., & Caudullo, G. (2016). Aesculus hippocastanum in Europe: distribution, habitat, usage and threats. European Atlas of Forest Tree Species. Publication Office of the European Union, Luxemburg, 60.
6. Sánchez de Lorenzo-Cáceres, JM (2014) Spanish Ornamental Flora. Aesculus hippocastanum L. Recovered in: arbolesornamentales.es
7. Vogel, A. (2018) Encyclopedia of Plants. Aesculus hippocastanum L. Recovered in: avogel.es