Black Locust or False Acacia
Robinia pseudoacacia. FABACEAE (Formerly LEGUMINOSAE).
Planting and Growing Black Locust Trees
You’ll find everything you need to know to plant and grow black locust or false acacia trees in the accompanying table’s tabs:
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- Flowers, foliage, and fruit of black locust or false acacia trees
- Growing conditions for black locust or false acacia
- When to plant black locust or false acacia
- How to plant black locust or false acacia
- How to prune black locust or false acacia
- Watering, fertilizing, and care of black locust or false acacia
- Landscape uses of black locust or false acacia
- Pest and disease control for black locust or false acacia
Growing Black Locust Trees
Many cultivars of fast- to medium-growing, upright, round-crowned, open, thorny, deciduous trees, to 75 ft. (23 m) tall, with frondlike, green leaves, 8–12 in. (20–30 cm) long, divided into 9-paired oval leaflets, turning yellow in autumn, and with black or deep brown, roughly furrowed bark.
Black Locust Planting and Care Guide
Flowers and Fruit
Depending on the species, many or few, fragrant, pealike, white flowers, borne in dangling clusters, 3–4 in. (75–100 mm) long, in late spring, form reddish brown, podlike fruit, to 4 in. (10 cm) long, containing a row of seed and persisting into winter.
Best Climates
U.S.D.A. Plant Hardiness Zones 3–10. Best with some winter chill.
Soil Type and Fertility
Damp to dry, well-drained soil. Fertility: Average–low. 6.0–7.5 pH. Salt tolerant.
Where and How to Plant
Full sun. Space 10–20 ft. (3–6 m) apart, depending on species.
Proper Care
Easy. Allow soil surface to dry between waterings until established. Drought tolerant. Avoid fertilizing. Prune to thin, remove suckers in summer. Propagate by cuttings, division, grafting, seed, suckers.
About This Species
Good choice for low-fertility soil in arid, open gardens. Drops flowers, pods, requiring maintenance. Invasive. Shallow rooted. Locust borer, leaf miner, scale susceptible.