Black Locust

How to grow Black Locust

Written by the GardenDecoded editorial team · Last reviewed 21 July 2026 · Written for UK gardens · How we research our guidance

Planting

Plant in autumn or early spring in an open, sunny position sheltered from strong wind. Stake young trees properly for the first few years — the wood is brittle and the crown catches wind. Keep it well away from drains, paving and lawns, as it suckers persistently from damaged roots.

Pruning

Prune in late summer or early autumn to limit bleeding, taking out dead and crossing wood. Avoid hard cutting back, which provokes a mass of vigorous, weakly attached regrowth. Remove suckers at the root rather than cutting them at ground level, or you get three back for every one.

Propagation

Suckers and root cuttings are the simplest route. Seed germinates after scarification and soaking, though named forms will not come true from it.

Pests and diseases

Largely untroubled by pests in the UK. The main problem is limb failure — branches break out in summer gales, so inspect mature trees over paths and seating.

Value to wildlife

The hanging white flower racemes are heavily worked by bees in June and produce a distinctive honey.

Notes

It fixes nitrogen and will thrive on rubble and poor urban soil where little else does, but it is a spreader — suckering, self-seeding and considered invasive in parts of Europe. Think carefully before planting it near open countryside. All parts including the bark and seeds have a poisonous reputation, so check its toxicity status before planting where children or pets have access.

This guidance was researched and written by GardenDecoded — see our editorial policy for how guides are checked and reviewed.

Other names for this plant

These names have all been used for Robinia pseudoacacia but are no longer the accepted name. You may still meet them on old labels, in books, or in nursery catalogues.

Others in Robinia