Red Horse Chestnut (Aesculus x carnea)

At a glance

Lifecycle: Perennial (hardy)
Exposure: Full sun
Frost limit: −34.4 °C

Cultivation

Prefers a deep loamy well-drained soil but is not too fussy. The dormant tree tolerates temperatures down to at least -15°c. There are some named forms selected for their ornamental value. Most members of this genus transplant easily, even when fairly large. Abnormal cell development in this species may result in eruptions on trunks over 30cm in diameter - these ultimately decay. Although a hybrid species, it breeds true from seed due to a doubling of the chromosomes.

Propagation

Seed - best sown outdoors or in a cold frame as soon as it is ripe.

Edible uses

We have no details for this species, but the following notes almost certainly apply to it. Seed - cooked. It can be dried, ground into a flour and used as a gruel. The seed is quite large, about 20mm in diameter, and is also easily harvested. Unfortunately, it is rich in saponins and these toxins need to be removed before the seed can be eaten. 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. Most of the minerals etc would also have been leached out by this treatment[K].

Medicinal uses

The plant is used in Bach flower remedies - the keywords for prescribing it are 'Excessive fear' and 'Anxiety for others'.

Material uses

Saponins in the seed are 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[K].