Horse chestnut
Aesculus spp

Family: Sapindaceae

What it is like

Aesculus spp comprises 13–19 species of flowering plants in the soapberry and lychee family. They are trees and shrubs native to the temperate Northern Hemisphere, with six species native to North America and seven to 13 species native to Eurasia. Also, several hybrids occur. They have good edible, medicinal and other uses. See individual species for more information.

Aesculus spp is a deciduous Tree growing to 30 m (98ft) by 25 m (82ft) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 4. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in heavy clay and nutritionally poor soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry or moist soil. The plant can tolerates strong winds but not maritime exposure. It can tolerate atmospheric pollution.

Height (m): 30

Where it is found

Trees and shrubs native to the temperate Northern Hemisphere, with six species native to North America and seven to 13 species native to Eurasia.

N. Temperate.

Conservation Status: Vulnerable C2a(i)

Countries/locations it is found in

Native to the temperate Northern Hemisphere, with six species native to North America and seven to 13 species native to Eurasia.

How it is used

Food

Rating: 4

The roasted seed is used as a coffee substitute. Seed - cooked. It can be dried, ground into a powder and used as a gruel. The seed is quite large, about 3cm in diameter, and is easily harvested. It is usually produced in abundance in Britain. Unfortunately the seed is also rich in saponins, these must be removed before it can be used as a food and this process also removes many of the minerals and vitamins, leaving behind mainly starch. See also the notes above on toxicity. The seed contains up to 40% water, 8 - 11% protein and 8 - 26% toxic saponins. The following notes apply to A. californica, but are probably also relevant here: The seed needs to be leached of toxins before it becomes safe to eat - the Indians would do this by slow-roasting the nuts (which would have rendered the saponins harmless) and then cutting them into thin slices, putting them into a cloth bag and rinsing them in a stream for 2 - 5 days.

Seed: includes nuts, cereals, peas and beans.

Medicine

Rating: 4

Various medicinal qualities depending on the species. They include: Alterative; Analgesic; Antiinflammatory; Antirheumatic; Astringent; Bach; Diuretic; Expectorant; Febrifuge; Haemostatic; Narcotic; Tonic; Vasoconstrictor; Vulnerary.

Other

Rating: 4

Saponins in the seed are used as a soap substitute. The saponins can be easily obtained by chopping the seed into small pieces and infusing them in hot water. This water can then be used for washing the body, clothes etc. Its main drawback is a lingering odour of horse chestnuts. The seed contains variable amounts of saponins, up to a maximum of 10%. A starch obtained from the seed is used in laundering. The bark and other parts of the plant contain tannin, but the quantities are not given. A yellow dye is obtained from the bark. The flowers contain the dyestuff quercetin. Wood - soft, light, not durable. Of little commercial value, it is used for furniture, boxes, charcoal. Carbon Farming Solutions - Industrial Crop: starch, medicinal (Crops grown for non-food uses. Industrial crops provide resources in three main categories: materials, chemicals, and energy. Traditional materials include lumber and thatch, paper and cardboard, and textiles).

Hypothetical Crop: These are perennial plants that could potentially be developed for cultivation. Some, such as cycads (for industrial starch), as simply neglected; others, such as buckwheat and soybeans, are annual crops that could potentially be perennialised by crossing and relatives.

Industrial Crop: Medicinal: Most pharmaceuticals are synthesized from petroleum but 25% of modern medicines are based on plants.

Industrial Crop: Starch: Materials and chemicals include bioplastics, paper, cardboard, solvents, paints, glues etc. Plants are usually pods, starchy fruits, nuts & seeds, starchy trunks.

Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.

Hypothetical Crop: These are perennial plants that could potentially be developed for cultivation. Some, such as cycads (for industrial starch), as simply neglected; others, such as buckwheat and soybeans, are annual crops that could potentially be perennialised by crossing and relatives.

Industrial Crop: Medicinal: Most pharmaceuticals are synthesized from petroleum but 25% of modern medicines are based on plants.

Industrial Crop: Starch: Materials and chemicals include bioplastics, paper, cardboard, solvents, paints, glues etc. Plants are usually pods, starchy fruits, nuts & seeds, starchy trunks.

Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.

Carbon Farming: Plants that can be a critical part of the solution to climate problems. The Carbon Farming Solution - Eric Toensmeier.

How it is grown

Climate: cold to warm temperate, Mediterranean.Humidity: semi-arid to humid. Landscape Uses: Firewood, Pollard, Specimen, Street tree. Prefers a deep loamy well-drained soil but is not too fussy tolerating poorer drier soils. Tolerates exposed positions and atmospheric pollution. A very ornamental and fast-growing tree, it succeeds in most areas of Britain but grows best in eastern and south-eastern England. Trees are very hardy when dormant, but the young growth in spring can be damaged by late frosts. The flowers have a delicate honey-like perfume. Trees are tolerant of drastic cutting back and can be severely lopped. They are prone to suddenly losing old heavy branches. The tree comes into bearing within 20 years from seed. Most members of this genus transplant easily, even when fairly large. Special Features: Attractive foliage, Not North American native, Naturalizing, Blooms are very showy. Carbon Farming Solutions - Cultivation: hypothetical. Management: standard (Describes the non-destructive management systems that are used in cultivation).

Propagating it: Seed - best sown outdoors or in a cold frame as soon as it is ripe. The seed germinates almost immediately and must be given protection from severe weather. The seed has a very limited viability and must not be allowed to dry out. Stored seed should be soaked for 24 hours prior to sowing and even after this may still not be viable. It is best to sow the seed with its 'scar' downwards. If sowing the seed in a cold frame, pot up the seedlings in early spring and plant them out into their permanent positions in the summer.

Best place to grow:

Habit: Tree

Hardiness: 4-9

Growth: Fast

Soil: Light (sandy), medium, heavy (clay)

Shade: Semi-shade, no shade

Moisture: Dry, moist

Things to keep in mind

The seed is rich in saponins. Although poisonous, saponins are poorly absorbed by the human body and so most pass through without harm. Saponins are quite bitter and can be found in many common foods such as some beans. They can be removed by carefully leaching the seed or flour in running water. Thorough cooking, and perhaps changing the cooking water once, will also normally remove most of them. However, it is not advisable to eat large quantities of food that contain saponins. Saponins are much more toxic to some creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish. Avoid in patients with kidney or liver disease. Avoid if taking warfarin as can interfere with anticoagulant therapy .

Its other names

Local names

Aesculus species. Varieties called buckeye and horse chestnut

Synonyms

Many. See individual species.