Is Black Locust a hardwood?

May 24, 2024

Is Black Locust a hardwood? Beauty, durability, sustainability, and style. Black Locust is one of the up-and-coming hardwood species with good reason.

Beauty, durability, sustainability, and style—it’s hard not to love the look and feel of hardwoods. Black Locust is one of the up-and-coming hardwood species—with good reason. If you’d like to use this hardwood to enhance your home, architectural project, or landscape, first take a moment to learn more about its properties and characteristics.

What is Black Locust wood?

Black Locust is a highly durable hardwood that has been used for hundreds of years. It has a unique tight-grain pattern with beautiful detail. Black Locust trees are also known as Robinia pseudoacacia, Robinia, Acacia, False Acacia. Black Locust is native to the United States but is widespread globally. Black Locust is a medium-sized tree, generally 40 to 60 ft (12 to 18 m) in height and 12 to 30 in (30 to 76 cm) in diameter. 

Black Locust lumber, also known as Robinia pseudoacacia, Robinia, Acacia, False Acacia.

Characteristics of Black Locust hardwood

Black locust is superior to other hardwoods with a Janka hardness scale of 1,700 lbf (7,560 N). Black Locust is a difficult wood to cut. It is known for its knots, mineral streaks, checks, minor grub holes, and bark insertions. To ensure superior appearances, only the most appealing pieces qualify as Premium Grade. Black Locust is naturally water and rot-resistant and has anti-fungal properties. Due to its characteristics, it is most commonly used for exterior furniture and decking. 

Advantages of Black Locust hardwood


Architects most often select Black Locust for their natural beauty. And sure enough, Black Locust hardwood has beautiful detail, it is tight-grained, and has a unique set of colors. A newly installed Black Locust project will have a pale amber to light brown color. With time and exposure to the natural elements (rain, snow, and UV), Black Locust wood develops a silvery-gray patina. The color has a natural aesthetic generally loved by architects. The change in color does not affect the longevity and durability of the wood.

Black Locust lumber decking wood develops a silvery-gray patina over time. Haviland Mill Park | Clarksville, MD.


Black Locust wood has an outstanding 50+ years of natural longevity without the use of ANY toxic chemicals. Due to its water and rot-resistant properties, it is ideal for a wide variety of outdoor applications. When properly dried, Black Locust has excellent dimensional stability and minimal shrinkage.


Though tropical hardwoods are more widespread, illegal harvesting of rainforests is a huge environmental issue. Another concern is that toxic oils and chemicals are necessary to clean and maintain tropical hardwood surfaces. In comparison, Black Locust hardwood is a native species and not endangered. Its fast and easy growth habit makes Black Locust wood a sustainable hardwood. No oils or chemicals are necessary to maintain the wood’s natural beauty making Black Locust an organic product.

Black Locust honey production also known as Acacia honey.

Low maintenance

We understand there is huge confusion around whether it is necessary to use decking oils on Black Locust wood surfaces or not. As experts, we strongly recommend NOT to use oils and chemicals to treat Black Locust hardwood surfaces. We have seen the damage oils can do to this naturally beautiful surface and transform the otherwise low-maintenance decking lumber into something with high-maintenance needs. 

Black Locust decking for prominent architectural project of Facebook Headquarters, Menlo Park, California.

What do you use black locust wood for?

Black Locust Lumber is a multifaceted type of wood. It is a type of hardwood used in exterior projects that require waterproof materials, especially for Decking and Boardwalks, Site Furnishings, RainScreens, Brise Soleil, and ProFlow Permeable Pavers. We are proud to have worked on incredible architectural design projects for Facebook Headquarters, Menlo Park, California, and the Dorchester Square Park in Montréal, Québec to name a couple. Black Locust is also the basis of commercial honey production also known as Acacia honey. Black Locust trees also enrich poor soils by fixing nitrogen.

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