The illustrated growing guide
Black Locust
Robinia pseudoacacia
Family Fabaceae
Est. zones 4-8
The permaculture powerhouse with an asterisk: nitrogen-fixing pioneer, rot-proof fence posts, premium honey, edible flower fritters — and it suckers/self-sows enough to be regulated in some states. On a farm with a mower it's an asset; in a subdivision it's a lawsuit. Check local status.
Full Sun
Low water
VERY FAST growth
Deer-resistant
Native to North America
Attracts bees
From the print shop
Growing black locust? Hang it.
Our Flowering Trees collection carries black locust — Robinia pseudoacacia, print Nº 11, “Black Locust.”
16 designsfrom $21.99white or black groundmatte poster, unframed
I
Overview
Will black locust suit your garden, and what goes wrong.
Will it fruit where you are?
Enter your ZIP — we look up your USDA hardiness zone (2023 map) and check it against what black locust actually needs.
Hardy inZones 4-8Black Locust at a glance
Common black locust problems
- Locust Borer (the one real enemy — stressed trees)
- Leaf Miner
- Heart Rot in old wounds
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Growing
Light, water, soil, propagation and the season’s jobs.
How to grow black locust: light, water & soil
How to plant & propagate black locust
When to spray black locust
Growing season. Vigorous trees outgrow most issues.
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The year
What black locust asks for, month by month.
The black locust year, month by month
BloomPruneWhat each band means
- Bloom — flowers open — pollinators working, frost on blossoms is the danger.
- Prune — shape it now — cuts heal cleanly and structure is visible.
The black locust year as text
- Jan pruning
- Feb pruning
- Mar quiet month
- Apr quiet month
- May bloom
- Jun bloom
- Jul quiet month
- Aug quiet month
- Sep quiet month
- Oct quiet month
- Nov quiet month
- Dec pruning
These are the species' typical months — expect them a few weeks earlier in warm zones and later in cold ones. Watch the plant, not just the calendar.
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Ecology & uses
What it does for the garden, and what it is grown for.
Black Locust in the garden system
- Canopy layer tree
- N-fixer
- Nectary/insectary
What black locust is grown for
⚠ Toxic if eatenALL parts toxic EXCEPT the flowers (bark/seeds significantly; livestock caution)
Harvesting & storing black locust
FLOWERS are edible (fritters!); WOOD: fence posts that outlast the farmer (30-50 yrs in ground).
Edibility, identification, and traditional-use notes here are general reference — not medical or veterinary advice, and not a claim that any plant treats or prevents anything. Medicinal ratings record how strongly a plant features in herbal tradition, nothing more. Never eat or dose a plant you have not positively identified. More on how to use this library.
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Cultivars
Named varieties of black locust, ruled as a catalogue.
Best black locust varieties & cultivars
'Purple Robe' (ornamental); straight species (posts + honey); 'Shipmast' (timber form)
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Sources & plant ID
Where the care distinctions come from, and how the plant is filed.
Research basis
Sources behind this profile
No extension citations are attached to black locustyet. The care figures below come from the library's own catalogue rather than a traced primary source.
Plant ID
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Where to buy
Third-party nurseries — not Story Thyme Farms.
Third-party nurseries, not Story Thyme Farms. Prices are theirs.
Story Thyme Farms may earn a small commission from these links, at no cost to you — it never changes what we recommend.
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Questions
Black Locust questions, answered straight.
Do deer eat black locust?
Rarely — black locust is considered deer-resistant, which makes it one of the safer unfenced choices in deer country. Hungry deer in a hard winter test every rule, but it's a low-risk pick.
Is black locust safe for kids and pets?
No — treat it as toxic if eaten. ALL parts toxic EXCEPT the flowers (bark/seeds significantly; livestock caution) Site it accordingly if children or pets roam the garden. This is general reference, not medical or veterinary advice — call a vet or poison control if something has actually been eaten.
When do you harvest black locust?
FLOWERS are edible (fritters!); WOOD: fence posts that outlast the farmer (30-50 yrs in ground).
How do you propagate black locust?
Seed (stratify), cuttings, or layering.
IX
Elsewhere
Where black locust sits in the library.
Sassafras
Eastern Hemlock
Northern Catalpa
American Sycamore