Practical
Plants

Robinia pseudoacacia

Black Locust

a perennial woody deciduous member of the Robinia genus in the family Leguminosae.

No photo available

Taxonomy and growth

Genus
Robinia
Life cycle
perennial
Foliage
deciduous
Woodiness
woody
Growth rate
vigorous
Height
25 m
Spread
15 m
Fertility
Bees
Flower type
hermaphrodite
Pollinators
Bees

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

All parts of the plant (except the flowers) and especially the bark, should be considered to be toxic[27][34][36]. The toxins are destroyed by heat[34].

Edible uses

This section contains historical Plants For A Future notes marked noncommercial.

Seed - cooked[13][30][33]. Oily[8]. They are boiled and used like peas[11]. After boiling the seeds lose their acid taste[17]. The seed is about 4mm long and is produced in pods up to 10cm long that contain 4 - 8 seeds[39]. A nutritional analysis is available[18]. Young seedpods - cooked[3]. The pods contain a sweetish pulp that is safe to eat and is relished by small children[16].(This report is quite probably mistaken, having been confused with the honey locust, Gleditsia spp[K].) A strong, narcotic and intoxicating drink is made from the skin of the fruit[6]. Piperonal is extracted from the plant, it is used as a vanilla substitute[3]. 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[35][11]. They can also be made into a pleasant drink[11].

Product or use
Condiment
Product or use
Drink
Product or use
Oil
Plant part
Flowers
Plant part
Seed
Plant part
Seedpod

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

Febrifuge[6][29]. The flowers are antispasmodic, aromatic, diuretic, emollient and laxative[18]. They are cooked and eaten for the treatment of eye ailments[18]. The flower is said to contain the antitumor compound benzoaldehyde[26]. The inner bark and the root bark are emetic, purgative and tonic[27][35][18][25]. The root bark has been chewed to induce vomiting, or held in the mouth to allay toothache[19][25], though it is rarely if ever prescribed as a therapeutic agent in Britain[27]. The fruit is narcotic[6]. This probably refers to the seedpod. The leaves are cholagogue and emetic[35]. The leaf juice inhibits viruses[18].

Product or use
Antispasmodic
Product or use
Antiviral
Product or use
Aromatic
Product or use
Cholagogue
Product or use
Diuretic
Product or use
Emetic
Product or use
Emollient
Product or use
Febrifuge
Product or use
Laxative
Product or use
Narcotic
Product or use
Purgative
Product or use
Tonic
Product or use
Cancer

Material uses

This section contains historical Plants For A Future notes marked noncommercial.

A drying oil is obtained from the seed[13][35]. An essential oil is obtained from the flowers. Highly valued, it is used in perfumery[35][31][2]. A yellow dye is obtained from the bark[20]. 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[26]. The bark contains tannin, but not in sufficient quantity for utilization[20]. On a 10% moisture basis, the bark contains 7.2% tannin and the heartwood of young trees 5.7%[20]. The bark is used to make paper and is a substitute for silk and wool[6]. Trees sucker freely, especially if coppiced, and they can be used for stabilizing banks etc[15][21]. 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[27][35][4][6][29][33][39][7][10][22]. A very good fuel[39], but it should be used with caution because it flares up and projects sparks[21]. 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%[26].

Product or use
Dye
Product or use
Essential
Product or use
Fibre
Product or use
Fuel
Product or use
Wood

Ecology and functions

Ecosystem niche
Canopy

Environment

Range
Eastern N. America - Appalachian and Ozark mountain ranges. Naturalized in Britain[9].
Habitat
Woods and thickets[28], especially in deep well-drained calcareous soils[7].
Light
full sun
Shade tolerance
no shade
Water
moderate
Hardiness
Zone 3+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Drainage
well drained
Tolerances
drought
Tolerates Nutritionally Poor Soil
No
Drought
tolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Seed - pre-soak for 48 hours in warm water and sow the seed in late winter in a cold frame[38]. A short stratification improves germination rates and time[38]. 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[37][41]. The seed stores for over 10 years[5]. Suckers taken during the dormant season.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

Succeeds in any well-drained soil, preferring one that is not too rich[1][15]. Succeeds in dry barren sites, tolerating drought and atmospheric pollution[32][15]. Succeeds in a hot dry position. The plant is reported to tolerate an annual precipitation in the range of 61 to 191cm, an annual temperature in the range of 7.6 to 20.3°C and a pH of 6.0 to 7.0[26]. A fast-growing tree for the first 30 years of its life[12][26], it can begin to flower when only 6 years old, though 10 - 12 years is more normal[23]. The flowers are a rich source of nectar and are very fragrant[39] with a vanilla-like scent[24]. The branches are brittle and very liable to wind damage[15]. When plants are grown in rich soils they produce coarse and rank growth which is even more liable to wind damage[4][15]. The plants sucker freely and often form dense thickets, the suckers have vicious thorns[21]. There are some named varieties selected for their ornamental value[12], some of these are thornless[21]. Any pruning should be done in late summer in order to reduce the risk of bleeding[15]. The leaves are rich in tannin and other substances which inhibit the growth of other plants[6]. A very greedy tree, tending to impoverish the soil[6]. (Although a legume, I believe it does not fix atmospheric nitrogen[K]) A very good bee plant[35][6][14][16]. This species is notably resistant to honey fungus[40][15].

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

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  2. Polunin. O. Flowers of Europe - A Field Guide. Oxford University Press 1969-00-00 ISBN 0192176218

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  3. Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00

    ↩1↩2

  4. Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981-00-00

    ↩1↩2

  5. Dirr. M. A. and Heuser. M. W. The Reference Manual of Woody Plant Propagation. Athens Ga. Varsity Press 1987-00-00 ISBN 0942375009

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  6. Triska. Dr. Hamlyn Encyclopaedia of Plants. Hamlyn 1975-00-00 ISBN 0-600-33545-3

    ↩1↩2↩3↩4↩5↩6↩7↩8

  7. Vines. R. A. Trees of Central Texas. University of Texas Press 1987-00-00 ISBN 0-292-78958-3

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  8. Yanovsky. E. Food Plants of the N. American Indians. Publication no. 237. U.S. Depf of Agriculture.

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  9. Clapham, Tootin and Warburg. Flora of the British Isles. Cambridge University Press 1962-00-00

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  10. Hill. A. F. Economic Botany. The Maple Press 1952-00-00

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  11. Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9

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  12. Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990-00-00 ISBN 0-86318-386-7

    ↩1↩2

  13. Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6

    ↩1↩2

  14. Riotte. L. Companion Planting for Successful Gardening. Garden Way, Vermont, USA. 1978-00-00 ISBN 0-88266-064-0

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  15. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4↩5↩6↩7

  16. Allardice.P. A - Z of Companion Planting. Cassell Publishers Ltd. 1993-00-00 ISBN 0-304-34324-2

    ↩1↩2

  17. Weiner. M. A. Earth Medicine, Earth Food. Ballantine Books 1980-00-00 ISBN 0-449-90589-6

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  18. Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. 1985-00-00 ISBN 0-917256-20-4

    ↩1↩2↩3↩4↩5

  19. Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. 1990-00-00 ISBN 0395467225

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  20. Rottsieper. E.H.W. Vegetable Tannins The Forestal Land, Timber and Railways Co. Ltd. 1946-00-00

    ↩1↩2↩3

  21. Lauriault. J. Identification Guide to the Trees of Canada Fitzhenry and Whiteside, Ontario. 1989-00-00 ISBN 0889025649

    ↩1↩2↩3↩4

  22. Vines. R.A. Trees of North Texas University of Texas Press. 1982-00-00 ISBN 0292780206

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  23. Elias. T. The Complete Trees of N. America. Field Guide and Natural History. Van Nostrand Reinhold Co. 1980-00-00 ISBN 0442238622

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  24. Genders. R. Scented Flora of the World. Robert Hale. London. 1994-00-00 ISBN 0-7090-5440-8

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  25. Moerman. D. Native American Ethnobotany Timber Press. Oregon. 1998-00-00 ISBN 0-88192-453-9

    ↩1↩2

  26. Duke. J. Handbook of Energy Crops - 1983-00-00

    ↩1↩2↩3↩4↩5

  27. Grieve. A Modern Herbal. Penguin 1984-00-00 ISBN 0-14-046-440-9

    ↩1↩2↩3↩4

  28. Fernald. M. L. Gray's Manual of Botany. American Book Co. 1950-00-00

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  29. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩1↩2

  30. Harris. B. C. Eat the Weeds. Pivot Health 1973-00-00

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  31. Schery. R. W. Plants for Man.

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  32. Hitchcock. C. L. Vascular Plants of the Pacific Northwest. University of Washington Press 1955-00-00

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  33. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

    ↩1↩2

  34. Frohne. D. and Pf�nder. J. A Colour Atlas of Poisonous Plants. Wolfe 1984-00-00 ISBN 0723408394

    ↩1↩2

  35. Chiej. R. Encyclopaedia of Medicinal Plants. MacDonald 1984-00-00 ISBN 0-356-10541-5

    ↩1↩2↩3↩4↩5↩6↩7

  36. Cooper. M. and Johnson. A. Poisonous Plants in Britain and their Effects on Animals and Man. HMSO 1984-00-00 ISBN 0112425291

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  37. Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948-00-00

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  38. McMillan-Browse. P. Hardy Woody Plants from Seed. Grower Books 1985-00-00 ISBN 0-901361-21-6

    ↩1↩2

  39. Sargent. C. S. Manual of the Trees of N. America. Dover Publications Inc. New York. 1965-00-00 ISBN 0-486-20278-X

    ↩1↩2↩3↩4

  40. RHS. The Garden. Volume 112. Royal Horticultural Society 1987-00-00

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  41. Gordon. A. G. and Rowe. D. C. f. Seed Manual for Ornamental Trees and Shrubs.

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