Also known as Black Locust Tree · Bristly Locust · Common Acacia
Safety note: This plant may be toxic to humans and pets. See toxicity details.
Black locust (Robinia pseudoacacia) is a fast-growing deciduous tree with fragrant white flowers, thorny branches, and valuable, durable wood.
At-a-glance light, water, soil, and growing conditions from plant data
Full Sun
100% intensity
Requires at least 6-8 hours of direct sunlight per day for optimal growth and flowering.
Drought Tolerant
25% intensity
Allow soil to dry out between waterings; established plants need very little supplemental water.
Well-drained, tolerates a wide range of soil types including poor and dry soils.
50% intensity
Adaptable
50% intensity
Hardy and adaptable to various temperature extremes once established, tolerating both heat and cold.
Outdoor
50% intensity
Low Need
25% intensity
Requires minimal fertilization; nitrogen-fixing roots reduce the need for supplemental nutrients.
Safety information from plant toxicity data
| Attribute | Value |
|---|---|
| Toxic for humans | Yes 4/5 intensity |
| Toxic for pets | Yes 5/5 intensity |
| Edible | No |
All parts of the plant are toxic, especially the bark, leaves, and seeds, due to the presence of lectins and robin.
Key traits and growing stats from plant data
Watering, pruning, propagation, and repotting details from plant data
Black locust is highly drought-tolerant once established. Water deeply but infrequently, allowing the soil to dry out considerably between waterings. Overwatering can lead to root rot.
Young plants require more consistent moisture until their root systems develop fully.
Prune black locust primarily to remove dead, damaged, or crossing branches. It can also be pruned to shape young trees or control size.
The best time for structural pruning is during the dormant season (late winter to early spring) before new growth begins.
Robinia pseudoacacia is easily propagated by seed, which often requires scarification or stratification to germinate. It also readily reproduces vegetatively through root suckers.
These suckers can be dug up and transplanted in the dormant season.
Repotting is typically not applicable to Robinia pseudoacacia as it is a large tree usually planted directly into the ground. If it were grown in a container for a very short period, repotting would occur when the root ball becomes crowded, likely in early spring.
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Monthly activity intensity for bloom and fruit across both hemispheres.
Flowering & fruiting calendar
Flowering & fruiting calendar
Photos of Black Locust (Robinia pseudoacacia)
Where Black Locust (Robinia pseudoacacia) is found
Density
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Common names and botanical synonyms
Botanical classification
| Rank | Name |
|---|---|
| Kingdom | Plantae |
| Division | Tracheophyta |
| Class | Magnoliopsida |
| Order | Fabales |
| Family | Fabaceae |
| Genus | Robinia |
| Species | Robinia pseudoacacia |
Similar in genus Robinia
Answers based on plant encyclopedia data
