Chinese Horse Chestnut
Aesculus chinensis
Family: Hippocastanaceae
What it is like
Aesculus chinensis is a deciduous Tree growing to 25 m (82ft) by 10 m (32ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 6 and is not frost tender. It is in flower in July, and the seeds ripen in September. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.
Height (m): 25
Where it is found
Mountains of Szechwan
E. Asia - N. China.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 3
Seed - cooked. It can be dried and ground into a powder and used as a gruel. The seed is quite large, it can be 3cm in diameter, and is easily harvested. Unfortunately it 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 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: 1
The seed is antirheumatic and emetic. The sweet tasting seed is said to be used in the treatment of contracted limbs that are due to palsy or rheumatism. It is also used in the treatment of stomach aches.
Antirheumatic: Treats rheumatism.
Emetic: Induces vomiting.
Other
Rating:
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.
Soap: Plants used directly as a soap substitute.
Wood: A list of the trees and shrubs that are noted for having useful wood.
How it is grown
Prefers a deep loamy well-drained soil but is not too fussy. Plants grow best in eastern and south-eastern areas of England, probably needing a continental climate in order to thrive. Although the trees are very hardy when dormant, the new growth can be damaged by late spring frosts. Most members of this genus transplant easily, even when fairly large.
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: Woodland Garden Canopy;
Habit: Tree
Hardiness: 5-9
Growth: Slow
Soil: Light (sandy), medium, heavy (clay)
Shade: Semi-shade, no shade
Moisture: 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.