Gymnocladus dioica - (L.)K.Koch.
(L.)K.Koch.
Kentucky Coffee Tree
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gbif· cc-by-nc
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gbif· cc-by-nc
Emily
Description
Gymnocladus dioica is a deciduous Tree growing to 20 m (65ft) by 15 m (49ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 4. It is in flower in June, and the seeds ripen in October. The species is dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required). . The plant is not self-fertile. It can fix Nitrogen. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very alkaline and saline soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought. It can tolerate atmospheric pollution.
Edible Uses
Coffee. Seedpod - raw or cooked. The roasted seeds can be eaten like sweet chestnuts. The pulp is sweet. A flavour like caramel. The pods are up to 25cm long and 5cm wide. The roasted seed is a caffeine-free coffee substitute. A bitter flavour. Thorough roasting for at least 3 hours at 150°c is necessary in order to destroy the poisonous hydrocyanic acid that is found in the seed. Seed - roasted and eaten like a nut. The seed contains toxic substances, see notes above.
Medicinal Uses
Homeopathy Miscellany. The pulverised root bark is used as an effective enema. A tea made from the bark is diuretic. It is used in the treatment of coughs due to inflamed mucous membranes and also to help speed up a protracted labour. A snuff made from the pulverized root bark has been used to cause sneezing in comatose patients. A tea made from the leaves and pulp from the pods is laxative and has also been used in the treatment of reflex troubles. A decoction of the fresh green pulp of the unripe fruit is used in homeopathic practice.
Known Hazards
The ripe seed contains hydrocyanic acid. This toxin can be destroyed by thoroughly heating the seed for at least 3 hours at 150°c. The seed contains saponins. Although toxic, these substances are very poorly absorbed by the body and so tend to pass through without causing harm. They are also broken down by heat so a long slow baking can destroy them. Saponins are found in many plants, including several that are often used for food, such as certain beans. 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.
Distribution
Eastern and Central N. America - New York to Tennessee, west to Arkansas and South Dakota.
Where It Grows
Coming Soon
Cultivation
Requires a deep rich soil and a sunny position. Tolerates drought, atmospheric pollution, salt and limestone soils. A very cold-hardy plant, tolerating temperatures down to about -30°c. A very ornamental but slow growing tree, it rarely flowers in Britain, requiring more summer heat than it usually gets here. Trees in the wild seldom live longer than 100 years. The tree has a light canopy so does not cast much shade, making it a good tree to use for the top canopy of a woodland garden. Dioecious. Male and female plants must be grown if seed is required. Unlike most members of the Leguminosae, his species does not form nodules of nitrogen-producing bacteria on the roots.
Propagation
Seed - best sown in a greenhouse as soon as it is ripe. The seed can also be sown in early spring in a greenhouse. Scarification and pre-soaking the seed for 24 hours in warm water, especially if it has been stored, will improve germination. Make sure the seed has swollen after soaking, soak it again if it has not and, if it still does not swell, try filing away some of the seedcoat but be careful not to damage the embryo. As soon as they are large enough to handle, prick the seedlings out into fairly deep individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Consider giving them some protection against the cold for their first couple of winters outdoors Root cuttings 4cm long and 1cm thick in a greenhouse in December. Plant the roots horizontally in pots. Good percentage.
Other Uses
Insecticide Miscellany Soap Soil reclamation Wood. The fruit is high in saponins and is used as a soap. The leaves are used as a fly poison. Trees are planted on the spoil tips of mines to stabilize and reclaim the soil. Wood - coarse-grained, heavy though not hard, strong, very durable in contact with the soil, finishes to a fine lustre. A handsome wood, it weighs 43lb per cubic foot and is used for cabinet work, furniture, construction, fencing etc[46, 61, 82, 171, 229, 235].
