Black Locust, Yellow Locust
Robinia pseudoacacia
Family: Fabaceae or Leguminosae
What it is like
Bloom Color: White. Main Bloom Time: Early spring, Late spring, Mid spring. Form: Oval, Upright or erect.
Robinia pseudoacacia is a deciduous Tree growing to 25 m (82ft) by 15 m (49ft) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 3. It is in flower in June, and the seeds ripen from November to March. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. It can fix Nitrogen. It is noted for attracting wildlife. 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. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought. It can tolerate atmospheric pollution.
Height (m): 25
Where it is found
Woods and thickets, especially in deep well-drained calcareous soils.
Eastern N. America - Appalachian and Ozark mountain ranges. Naturalized in Britain.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 3
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.
Oil: Oil
Seed: includes nuts, cereals, peas and beans.
Seedpod: things such as Okra, French and Runner beans.
Condiment: the various plants that are used as flavourings, either as herbs, spices or condiments.
Drink: not including plant saps, tea or coffee substitutes.
Medicine
Rating: 2
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.
Antispasmodic: Relaxes muscular spasms and cramps, calming nervous irritation.
Antiviral: Treats virus diseases
Aromatic: Having an agreeable odour and stimulant qualities.
Cancer: Used in the treatment of cancer.
Cholagogue: Increases the flow of bile and its discharge from the body.
Diuretic: Acts on the kidneys, promoting the flow of urine.
Emetic: Induces vomiting.
Emollient: Softens the skin, causing warmth and moisture.
Febrifuge: Reduces fevers.
Laxative: Stimulates bowel movements in a fairly gentle manner.
Narcotic: Relieves pain, induces drowsiness and gives a sense of well-being.
Purgative: A drastic laxative causing a cleansing or watery evacuation of the bowels, usually with a griping pain.
Tonic: Improves general health. Slower acting than a stimulant, it brings steady improvement.
Other
Rating: 4
Agroforestry Uses: This species has been widely planted for shelterbelts and windbreaks, and is also used to produce woody biomass for energy production. It suckers freely, especially if coppiced, and can be used for stabilizing banks etc. It is used in restoration and rehabilitation projects because its extensive root system holds and stabilizes the soil surface, it sprouts vigorously and prolifically, it increases soil fertility through nitrogen fixation, and it forms a leaf litter that protects the soil. Its main use has been in the rehabilitation of former surface mine sites and for erosion control, but it is also used to rehabilitate contaminated soils, depleted soils, gravel pits, and logged areas, and to stabilize railroad embankments and highway edges. The plant is often found as a pioneer on old fields, burned areas, and lands strip-mined for coal. The leaves are rich in tannin and other substances which inhibit the growth of other plants. The flowers are a rich source of nectar. Honey produced from this nectar is considered to be of high quality and fetches a price premium. Other Uses: 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. The wood is close-grained, exceedingly hard, heavy, very strong (due to a high lignin content), resists shock and is very durable in contact with the soil. It weighs 45lb per cubic foot. It does not shrink much when drying. The wood is used in shipbuilding and for making fence posts, tree nails, flooring, furniture, woodenware etc. 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%. A very good fuel, but it should be used with caution because it flares up and projects sparks. The wood is also used for making charcoal. A dynamic accumulator gathering minerals or nutrients from the soil and storing them in a more bioavailable form - used as fertilizer or to improve mulch.
Dye: Plants that provide dyes.
Essential: Essential oils that are used in perfumery, medicines, paint solvents, insect repellents etc.
Fibre: Used for making cloth, rope, paper etc.
Fodder: Food given to the animals (including plants cut and carried to them) rather than forage for themselves.
Fuel: Usually wood, plant materials that have been mentioned as being a good fuel.
Oil: Vegetable oils have many uses, as lubricants, lighting, soap and paint making, waterproofing etc. This does not include the edible oils unless they are also mentioned as having other uses.
Soil stabilization: Plants that can be grown in places such as sand dunes in order to prevent erosion by wind, water or other agents.
Wood: A list of the trees and shrubs that are noted for having useful wood.
Agroforestry Services: Nitrogen: Plants that contribute to nitrogen fixation include the legume family – Fabaceae.
Agroforestry Services: Windbreak: Linear plantings of trees and shrubs designed to enhance crop production, protect people and livestock and benefit soil and water conservation.
Fodder: Bank: Fodder banks are plantings of high-quality fodder species. Their goal is to maintain healthy productive animals. They can be utilized all year, but are designed to bridge the forage scarcity of annual dry seasons. Fodder bank plants are usually trees or shrubs, and often legumes. The relatively deep roots of these woody perennials allow them to reach soil nutrients and moisture not available to grasses and herbaceous plants.
Industrial Crop: Biomass: Three broad categories: bamboos, resprouting woody plants, and giant grasses. uses include: protein, materials (paper, building materials, fibers, biochar etc.), chemicals (biobased chemicals), energy - biofuels
Management: Coppice: Cut to the ground repeatedly - resprouting vigorously. Non-destructive management systems maintaining the soil organic carbon.
Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.
Minor Global Crop: These crops are already grown or traded around the world, but on a smaller scale than the global perennial staple and industrial crops, The annual value of a minor global crop is under $1 billion US. Examples include shea, carob, Brazil nuts and fibers such as ramie and sisal.
Other Systems: SRC: Short-rotation coppice.
Agroforestry Services: Nitrogen: Plants that contribute to nitrogen fixation include the legume family – Fabaceae.
Agroforestry Services: Windbreak: Linear plantings of trees and shrubs designed to enhance crop production, protect people and livestock and benefit soil and water conservation.
Fodder: Bank: Fodder banks are plantings of high-quality fodder species. Their goal is to maintain healthy productive animals. They can be utilized all year, but are designed to bridge the forage scarcity of annual dry seasons. Fodder bank plants are usually trees or shrubs, and often legumes. The relatively deep roots of these woody perennials allow them to reach soil nutrients and moisture not available to grasses and herbaceous plants.
Industrial Crop: Biomass: Three broad categories: bamboos, resprouting woody plants, and giant grasses. uses include: protein, materials (paper, building materials, fibers, biochar etc.), chemicals (biobased chemicals), energy - biofuels
Management: Coppice: Cut to the ground repeatedly - resprouting vigorously. Non-destructive management systems maintaining the soil organic carbon.
Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.
Minor Global Crop: These crops are already grown or traded around the world, but on a smaller scale than the global perennial staple and industrial crops, The annual value of a minor global crop is under $1 billion US. Examples include shea, carob, Brazil nuts and fibers such as ramie and sisal.
Other Systems: SRC: Short-rotation coppice.
Attracts Wildlife: Plants noted for attracting wildlife
Carbon Farming: Plants that can be a critical part of the solution to climate problems. The Carbon Farming Solution - Eric Toensmeier.
Dynamic accumulator: Plants that gather minerals or nutrients from the soil and store them in a more bioavailable form and in high concentration in their tissues. Used as fertilizer or to improve mulch.
Food Forest: Plants for Edible Forest Gardens and Food Forests.
Nitrogen Fixer: Plants that fix nitrogen in the soil
Scented Plants: Plants noted for their scent
How it is grown
Landscape Uses:Erosion control, Firewood, Aggressive surface roots possible. Succeeds in any well-drained soil, preferring one that is not too rich. Succeeds in dry barren sites, tolerating drought and atmospheric pollution. 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. A fast-growing tree for the first 30 years of its life, it can begin to flower when only 6 years old, though 10 - 12 years is more normal. The flowers are a rich source of nectar and are very fragrant with a vanilla-like scent. The branches are brittle and very liable to wind damage. When plants are grown in rich soils they produce coarse and rank growth which is even more liable to wind damage. The plants sucker freely and often form dense thickets, the suckers have vicious thorns. There are some named varieties selected for their ornamental value, some of these are thornless. Any pruning should be done in late summer in order to reduce the risk of bleeding. The leaves are rich in tannin and other substances which inhibit the growth of other plants. A very greedy tree, tending to impoverish the soil. (Although a legume, I believe it does not fix atmospheric nitrogen) A very good bee plant. This species is notably resistant to honey fungus. Special Features: North American native, Invasive, Naturalizing, All or parts of this plant are poisonous, Attracts butterflies, Fragrant flowers, Blooms are very showy. The plant is heat tolerant in zones 9 through 3. (Plant Hardiness Zones show how well plants withstand cold winter temperatures. Plant Heat Zones show when plants would start suffering from the heat. The Plant Heat Zone map is based on the number of "heat days" experienced in a given area where the temperature climbs to over 86 degrees F (30°C). At this temperature, many plants begin to suffer physiological damage. Heat Zones range from 1 (no heat days) to 12 (210 or more heat days). For example Heat Zone. 11-1 indicates that the plant is heat tolerant in zones 11 through 1.) For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. A sprouting standard sending up shoots from the base. The root pattern is flat with shallow roots forming a plate near the soil surface. The root pattern is suckering with new plants from underground runners away from the plant.
Propagating it: 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.
Best place to grow: Woodland Garden Canopy;
Habit: Tree
Hardiness: 4-9
Growth: Fast
Soil: Light (sandy), medium, heavy (clay)
Shade: No shade
Moisture: Dry, moist
Things to keep in mind
All parts of the plant (except the flowers) and especially the bark, should be considered to be toxic. The toxins are destroyed by heat.