Black Locust is a fast-growing deciduous tree native to the Allegheny Mountains that has become a fixture of American homesteads and landscapes. Hardy in zones 4 through 8, it typically reaches 30 to 50 feet tall (occasionally to 80 feet) with a broadly columnar form and narrow oblong crown, spreading 15 to 20 feet wide on average. The tree produces delicate, fragrant flowers in May and early June that attract pollinators, followed by showy fruit pods. Beyond its ornamental appeal, Black Locust fixes nitrogen in the soil, tolerates drought and poor conditions with ease, and has been treasured for centuries for its rot-resistant wood and role in sustainable forestry.
Partial Sun
Moderate
4-8
360in H x 240in W
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Moderate
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Black Locust earned its place on colonial homesteads not through accident but through genuine utility and beauty combined. The fragrant flowers arrive in late spring, drawing bees and other pollinators with remarkable generosity. Its ability to thrive in sandy, nearly barren soils while simultaneously enriching them with fixed nitrogen makes it a working tree, not merely an ornamental one. Deer leave it untouched, urban pollution doesn't faze it, and it laughs at drought once established. The cultivar 'Umbraculifera' grows as a single-trunked tree with a refined habit, though gardeners should note it can become top-heavy and benefit from structural support.
Black Locust serves multiple roles in the landscape and beyond. It functions as a street tree in challenging urban conditions where other species fail, a flowering tree that supports pollinator populations through its abundant, fragrant May blooms, and a nitrogen-fixing tree that improves soil for surrounding plantings. Historically and today, its wood is valued for firewood production, fence posts, and other structures requiring decay resistance. The tree also naturalizes well in informal settings and performs exceptionally in maritime climates where salt spray and wind are concerns.
No timeline data available yet for this variety.
Avoid pruning in spring, as Black Locust bleeds sap heavily during that period; defer any structural pruning until summer or fall. Remove root suckers and self-seeded seedlings as they appear unless you intend to naturalize the tree and allow thicket formation. The 'Umbraculifera' cultivar, when grown as a single-trunk tree, may develop a top-heavy form and benefit from early structural guidance or wind protection.
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“Black Locust belongs to a genus honored by name to Jean Robin, gardener to French kings Henri IV and Louis XIII in the 1600s, who received these North American natives and recognized their value. The species was originally confined to the Allegheny Mountains but escaped cultivation over centuries, naturalizing across much of the United States and southern Canada, eventually reaching Europe, Asia, and South America. The tree became indispensable to colonial America, favored equally as an ornament and as a practical resource for its nitrogen-fixing properties and famously rot-resistant wood. Of all trees prized by early settlers, the Raintree Nursery notes Black Locust stands among the most significant, a testament to both its adaptability and the genuine problems it solved in a working landscape.”