Herb: Black Locust

Latin name: Robinia pseudoacacia

Family: Leguminosae

Medicinal use of Black Locust:

Febrifuge. The flowers are antispasmodic, aromatic, diuretic, emollient and laxative. They are cooked and eaten for the treatment of eye ailments. The flower is said to contain the antitumor compound benzoaldehyde. The inner bark and the root bark are emetic, purgative and tonic. The root bark has been chewed to induce vomiting, or held in the mouth to allay toothache, though it is rarely if ever prescribed as a therapeutic agent in Britain. The fruit is narcotic. This probably refers to the seedpod. The leaves are cholagogue and emetic. The leaf juice inhibits viruses.

Description of the plant:


25 m
(82 feet)



Habitat of the herb:

Woods and thickets, especially in deep well-drained calcareous soils.

Edible parts of Black Locust:

Seed - cooked. Oily. They are boiled and used like peas. After boiling the seeds lose their acid taste. The seed is about 4mm long and is produced in pods up to 10cm long that contain 4 - 8 seeds. A nutritional analysis is available. Young seedpods - cooked. The pods contain a sweetish pulp that is safe to eat and is relished by small children.(This report is quite probably mistaken, having been confused with the honey locust, Gleditsia spp.) A strong, narcotic and intoxicating drink is made from the skin of the fruit. Piperonal is extracted from the plant, it is used as a vanilla substitute. No further details. All the above entries should be treated with some caution, see the notes at the top of the page regarding toxicity. Flowers - cooked. A fragrant aroma, they are used in making jams and pancakes. They can also be made into a pleasant drink.

Other uses of the herb:

A drying oil is obtained from the seed. An essential oil is obtained from the flowers. Highly valued, it is used in perfumery. A yellow dye is obtained from the bark. Robinetin is a strong dyestuff yielding with different mordants different shades similar to those obtained with fisetin, quercetin, and myricetin, with aluminum mordant, it dyes cotton to a brown-orange shade. The bark contains tannin, but not in sufficient quantity for utilization. On a 10% moisture basis, the bark contains 7.2% tannin and the heartwood of young trees 5.7%. The bark is used to make paper and is a substitute for silk and wool. Trees sucker freely, especially if coppiced, and they can be used for stabilizing banks etc. Wood - close-grained, exceedingly hard, heavy, very strong, resists shock and is very durable in contact with the soil. It weighs 45lb per cubic foot and is used in shipbuilding and for making fence posts, treenails, floors etc. A very good fuel, but it should be used with caution because it flares up and projects sparks. The wood of Robinia pseudoacacia var. rectissima, the so called "Long Island" or "Shipmast" locust, has a greater resistance to decay and wood borers, outlasting other locust posts and stakes by 50 - 100%.

Propagation of Black Locust:

Seed - pre-soak for 48 hours in warm water and sow the seed in late winter in a cold frame. A short stratification improves germination rates and time. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in the following summer. Other reports say that the seed can be sown in an outdoor seedbed in spring. The seed stores for over 10 years. Suckers taken during the dormant season.

Cultivation of the herb:

Woods and thickets, especially in deep well-drained calcareous soils.

Known hazards of Robinia pseudoacacia:

All parts of the plant (except the flowers) and especially the bark, should be considered to be toxic. The toxins are destroyed by heat.

Plant information taken from the Plants For A Future.