Invasive Watch: Locust

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Invasive Watch: Locust

Get tips on how to properly identify these two similar brush species, as well as control them.

What to Look For

Honeylocust is a deciduous, fast-growing, aggressive, thorny legume tree. The bark is grayish-brown and furrowed with long scaly ridges. The leaves are alternate, oval and 6 to 8 inches long.

Black locust is a deciduous, fast-growing, early succession, thorny legume tree. When mature, the bark is dark brown and deeply furrowed. The leaves are alternate along the stems, oval to rounded, dark green on top and pale beneath. Both honeylocust and black locust produce white fragrant flowers that appear May to June.

Where it is Found

Honeylocust is commonly found on utility and roadside rights-of-way, where it spreads rapidly from seeds, outcompeting native vegetation and forming dense thickets of trees.

Black locust prefers full sun and well-drained soils, and it poses a serious threat to native vegetation on utility and roadside rights-of-way and upland forest edges. It reproduces rapidly by root suckering and stump sprouts, which can regrow to form groves of trees. Both species can reach 40 to 100 feet in height at maturity.

How to Treat It

For control of honeylocust or black locust, apply 1 percent of Milestone® herbicide plus 20 percent to 25 percent v/v of Garlon® 4 Ultra herbicide in basal oil. This treatment may be made during any time of the year, including winter months. Late winter and early spring applications often provide optimum control.



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™ ® ℠ Trademarks and service marks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. When treating areas in and around roadside or utility rights-of-way that are or will be grazed, hayed or planted to forage, important label precautions apply regarding harvesting hay from treated sites, using manure from animals grazing on treated areas or rotating the treated area to sensitive crops. See the product label for details. State restrictions on the sale and use of Garlon 4 Ultra and Milestone apply. Consult the label before purchase or use for full details. Always read and follow label directions. Always read and follow label directions.


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