Black Locust: A Tree with Many Uses

In early October this past year, a devoted group of foresters, farmers, extension educations, students, and others gathered at the USDA Plant Materials Center in Big Flats, NY to discuss a common, yet underappreciated tree that has great potential for farms across the Northeast: Black Locust (Robinia pseudoacacia).

stand of black locust trees.

Steve Gabriel / Cornell Small Farms Program. Stand of black locust trees.

This tree, which has often been given a bad name for it’s opportunistic rapid growth and robust thorns, is said to be native originally to the Appalachian Mountain range, though it has become naturalized throughout the United States, southern Canada, and even parts of Europe and Asia. The species is incredibly adaptive, growing in many elevations, microclimates, and soil types.

While some have named it an “invasive” tree given its rapid growth and willingness to spread by seed and root suckering, others see these characteristics as advantageous, if only populations are properly managed to harness these qualities. Make no mistake, locust is not a tree to plant and walk away from. It is best when incorporated into managed activities on the farm, of which there are a remarkable array of options and benefits, including:

  • Because it fixes nitrogen from the atmosphere, the trees grow incredibly fast (3 – 4 feet in a season) and can quickly become windbreaks, shelterbelts, and shade and shelter for animals in silvopasture grazing systems.
  • The nutritional value of the leaves is similar to alfalfa, making it a valuable feed for ruminant livestock. Some sources claim excessive consumption can lead to toxicity, but many farmers have found their animals naturally limit their intake. (horses excepted)
  • The tree has been used to support nutrition in other crops, from grains to other trees. Research has shown increases in nitrogen in barley grain crops interplanted with locust, and black walnuts interplanted with locust as “nurse” trees were shown to rapidly increase their growth.
  • The flowers are important sources of food for honeybees. In Hungary, Black Locust is the basis of commercial honey production.
  • The high-density wood is the most rot resistant wood we can grow in our climate, making it an ideal material for fenceposts, hope poles, outdoor furniture, decks, and other projects that require weatherproof materials.
  • It’s BTU rating is among the highest, making it an excellent firewood in both heat value and coaling ability. At our last house, we actually ruined a woodstove by burning too much locust, which gets extremely hot.
young black locust tree

young black locust tree. Photo from Wikimedia

If anything, Black locust is almost too good at what is does. All theses attributes have resulted in an extraordinarily high demand; both sellers of locust poles and lumber, as well as those in the nursery trade at the meeting reported not even coming close to meeting the demand for their products. There is a lot of room in the market for more farmers to grow, harvest, and sell black locust products in many parts of the region.

The challenge? Some states prohibit importing, selling, or trading Black Locust, including Massachusetts and it is restricted in Minnesota, Michigan, and New York. This is not necessarily a complete list – check with your state regulators before deciding how to proceed. Each state has it’s own specific regulations.

In New York, a regulated plant cannot be knowingly introduced into a location where it isn’t already present. It’s hard to say if there is such a place in New York, and likely not in any location where farming traditionally occurred, since the tree has a long history of value to both Native Americans and colonizer settler farmers around the state. In any case, in New York the trees can be purchased, sold, propagated and transported legally. Nursery’s are required to attached a disclaimed to any material they sell.

Assuming you are clear to work with Black Locust, it’s important to consider the genetic stock you source trees from, especially if your goal is to grow straight poles or trees that can be milled for lumber. Locust is incredibly crooked in its “natural” form, and so seed selection, and sometimes pruning, is a critical factor for success. Ironically, the Hungarians identified the awesomeness of Black locust a long time ago (1700s), deciding to intentionally import seeds and engage in an intensive breeding program. As a result, some of the best stock today comes from Eastern Europe, and nearly 20% of the forests in Hungary are comprised of Black Locust.

Propagation of new trees is best achieved by either seed, or root cuttings. Of course, seed will express variety in the resulting genetic profile, whereas root cuttings will be clones of the parent tree. To grow from seed, the thick coat must first be broken, most often by soaking in a pot of boiling water for 12 – 24 hours. Root cuttings can be taken by finding a good flare in the tree, and digging up roots at least thumb thickness. Roots are cut into 2” sections and planted in a potting mix or prepared seed bed.

While the tree is suitable for a wide range of sites, avoid extremely heavy clay and soils with excessive water moisture (standing water). Soil prep can be minimal, as the trees can often compete and overtake other competitors quite easily. Protection from deer or other potential pests is critical during the establishment period, usually the first one to three years.

Black locust has just a few pests of concern, and a little observation and vigilance goes a long way. The health and vigor of the trees are important defenses against devastation, as research has shown that good growing conditions are more important than genetic resistance.

black locust logs

Brett Chedzoy / CCE. Black locust logs.

The most common pest is the Locust borer (Megacyllene robiniae) which most often attacks living, stressed trees, causing extensive damage to the quality of the wood. Identifying and removing infected trees can go a long way. It’s critical get to know the lifecycle of the pest. The other is main pest is the leaf miner (Odontota dorsalis), which attacks the tree in spring, turning the leaves brown by mid-summer or early fall. Overall tree growth can be impacted, but usually not seriously.

One of the most exciting conversations at the meeting was around the good economics for Black Locust, which can be summarized as demand far outstripping the supply. A recent blossoming of interest in natural and sustainable materials for garden and fence posts, coupled with a boom in the hop production industry in the Northeast mean that black locust polewood (which requires only harvesting and cutting to length) can alone be a valuable product from the farm woodlot. Larger, straight trees can also be milled and either sold as lumber or made into a wide range of products include outdoor furniture and offered at a premium price. Prices for these products range from $1 – $3 per linear foot for whole posts, and from $1.50 – $3.50/board foot for milled lumber, which is far above the prices for most conventional hardwood lumber.

Personally, at our farm, Black locust has found a nice in our pastures, where it quickly establishes itself and is able to be integrated with our sheep grazing paddocks in under 5 years. The sheep initially prune the lower limbs for feed, and we prune thicker branches to use for tree stakes, to plant more trees! We plant very close together (3 – 4 feet apart) so that over time, we can leave some trees as the overstory, while coppicing (cutting to the ground) and pollarding (cutting above browse height) the less straight ones to provide longer-term fodder reserves for the sheep. Eventually we can harvest some posts and poles, as well.

With all its functions and uses in the farm landscape, it’s a wonder more people aren’t planting these trees, and managing ones they already have. The key take away is; if you plant it, manage it. This wonderful tree has many benefits to harvest, but left along could become a problem plant on the farm.

Sources for Trees and Seeds:

Twisted Tree Farm, NY: http://twisted-tree.net/

Edible Acres, NY: http://edibleacres.org/

Sheffield’s Seeds, NY: https://sheffields.com

Cold Stream Farm, MI: https://www.coldstreamfarm.net

ore information and slides from the workshop can be found at: http://silvopasture.ning.com/forum/topics/growing-black-locust-as-a-timber-cash-crop-in-the-northeast

This article is available for download at Wellspring Forest Farm & School’s website: http://media.wellspringforestfarm.com

Steve Gabriel

Steve is an Extension Specialist focused on specialty mushroom production and agroforestry. Throughout his career, Steve has taught thousands of people about the ways farming and forestry can be combined to both benefit the ecology and economies of small farms.  He is also a farmer, author, hiker, and musician.

38 Comments

  1. Gary Chesbro on March 24, 2018 at 8:46 pm

    Is this considered an invasive species in Jefferson County. I have 8 acres in Ellisburg and would be interested in planting some.

    • Talia Isaacson on March 27, 2018 at 9:01 am

      Hi Gary – I’d recommend getting in touch with your local extension office (http://ccejefferson.org/). They will likely be able to provide you with a definitive answer. Good luck!

  2. Shelia ellis on August 11, 2018 at 9:38 am

    We moved into a home and the locust tree was cut down. How can we rid our yard from the root suckers?

  3. David white on October 10, 2018 at 9:35 am

    I am interested in ideas for establishing plantings in urban vacant lots. My city has many lots where houses have been torn down but where economics are not there to build. The lots are simply blocked off from street access and kept mowed. My thoughts were urban wooded lots maintained for the wood and potential bee keeping

  4. Heather Wood on December 1, 2018 at 12:53 pm

    I love blacklocust trees but was always told that the leaves were toxic to animals. Did this only apply to horses or was it altogether incorrect?

    • Kelsie Raucher on December 6, 2018 at 1:14 pm

      Hi Heather,
      I would recommend reaching out to the author of the article, Steve, with your question. He can be reached at sfg53@cornell.edu.

  5. Marcus Storms on December 26, 2018 at 7:22 pm

    Hi! This information is great! I just learned today that I have one of these trees, in bad shape, in my yard. I recently burned a large pile of underbrush and wood from cleaning the place up. Little ones began popping up all over! I’m glad I found out wgat they were. The existing tree has been there for at least 2 decades. It is beyond help, but I hope to coach the little ones into better trees. Any tips?

  6. Elvis Vancycle on January 2, 2019 at 9:19 pm

    Good article. I assume you don’t mean it when you say that to germinate, seeds should first be soaked in a pot of BOILING water for 12-24 hours. Sounds like bean soup!

    • Ralph Marshall on July 9, 2020 at 11:23 am

      I saw another video… The guy said he got water to boiling, turned it off, dropped the seeds in, and soaked for 24 hours… So… You’re right… You don’t actually boil the seeds the whole time…

  7. Gerard Fradette on February 11, 2019 at 11:13 am

    I understand form an elderly gentleman from Italy(now deceased)that the saplings of locust, were shaped in a curved shape conducive to using for a ship or boats bow and keel and used thus because of the trees rapid growth and rot resistance properties.

  8. P h on October 6, 2019 at 10:21 pm

    How to find a lumber company willing to cut and mill this wood i have not been successful here in WI locust is considered a weed with no market available

    • Kelsie Raucher on March 26, 2020 at 1:57 pm

      Hi P h,

      I’d recommend reaching out to your local extension team in WI with your inquiry: https://extension.wisc.edu/

      • Bill Long on November 19, 2020 at 9:56 pm

        I interplanted Black Locust trees with American chestnut and Black walnut trees over 25 years ago. The chestnuts are over 40 feet tall now. The Back walnuts have struggled.
        Black locust trees have a tendency to split, requiring diligent pruning. Most of the Black locust trees are over 40 feet tall now.

        Would coppicing these trees compromise the health of the chestnut and walnut trees?

        When i bought the farmland over 40 years ago. The land was depleted from over farming the clay soil. Hence the reason for interplanting Black locusts.

        You say there is a market for Black Locust wood?
        I have been using a local tree pruning agency, but they are uninterested in preparing the wood for marketing.
        My farm is in Oregon, and i don’t wan’t to pay for harvested wood i can’t sell.

        Thoughts and advice

    • Tim Keating on May 1, 2020 at 11:11 am

      You can contact Earthbilt (info@earthbilt.com) for help finding a mill interested in black locust.

  9. Brian on February 17, 2020 at 7:59 pm

    Musser Forests in PA is a much cheaper source for Black Locust.

  10. Bowsprite on May 16, 2020 at 6:20 am

    I live on the North Fork of Long Island (East Marion, NY) and birds drop black locust seeds onto my little garden. 2-feet tall little saplings come up every spring amid my wildflowers. I cut them off at the base, dry them and have excellent kindling. I love black locust!

  11. Deanne Bednar on June 14, 2020 at 1:12 pm

    Black Locust were planted – 4 ft spacing- for an agriforest project, 35 feet (legal) from an oil pipeline. Now I am concerned that over the years the trees might be a danger for the pipeline. I have considered cutting and poisoning the stump, and also coppicing above the 5 ft tree tube and managing the branches so they don’t go to seed (sounds like a lot of awareness and time).
    I am concerned that coppicing like this might actually trigger the tree to send out runners and have new little trees popping up.
    Any thoughts on this?

  12. Ralph Marshall on July 9, 2020 at 11:25 am

    Curious about climate zones and rainfall requirements… What’s the minimum yearly rainfall, and the optimum yearly rainfall… I sounds like a good hard cold winter is no problem…
    Thanks..

  13. Fredrick Schnebly on October 19, 2020 at 3:41 pm

    The flowers of the black locust tree are edible by humans. They smell and taste sweet and delicious. Honey made from them will be delicious also.

  14. David Head on October 29, 2020 at 6:01 pm

    In my experience, while the heartwood is very rot resistant, the sap wood is not.

    • Tina on November 26, 2022 at 3:35 pm

      My dad put up a locust post in the center front opening of a garage he built. It was to be temporary but, 49 years later it is still there. It still has the bark on it and is still solid. The diameter is about 10 or 12 inches. I’m impressed.

  15. HENRIETTA SAUNDERS on April 28, 2021 at 12:51 pm

    Please don’t plant this tree. It is taking over natural areas in the MidWest.

    • Jenny on May 8, 2021 at 8:42 pm

      I agree. This tree is very invasive. We get around 20 suckers a year and they aren’t easily removed. The thorns n the branches make handling the branches difficult and they trees themselves are weak and are easily broken during storms. There are better trees!!

      • Charlie Clark on August 18, 2021 at 9:20 am

        We are finding out the same thing! Invasive, indeed! In our field we have one acre of 3-5 foot saplings grounding among poison ivy. How do we rid ourselves of these insidious trees and root structures? I’m not a farmer, just a retiree trying to manage a small but sizable piece of land?

        • Laurel on September 17, 2021 at 9:06 am

          The best way I’ve found to ensure that suckers don’t keep coming up from old root structures is to soak the cut stump of anything I cut with Tordon RTU immediately after cutting.

    • Dawn Burgess on May 28, 2021 at 9:11 pm

      I just found out I have one large bush of it. I didn’t realize it was a tree, and a small one starting in another place in my back yard. I thought they were pretty until I looked it up and it says it’s poisonous to animals…I have a large dog that has been back there for a year and a half and has never gotten sick to my knowledge. But he’s an older dog and doesn’t chew on sticks anymore. But what if we got a new puppy? They chew on everything. Should I get rid of both trees because of the danger risk to them,? I’ve read that they are poisonous to sheep, cattle, horses, dogs, cats, if they eat the bark or other parts of the plant.

      • Allen on April 14, 2022 at 10:12 am

        I have found the opposite to be true. My dogs chew sticks from them, goats, cows and horses (occasionally) eat the leaves and the blooms are covered in bees. I even tried tasting the flowers.
        I’m no expert, just my observations.
        Unfortunately, many plants and fungi get a false bad rap online because of paranoia from overzealous pet owners.

        • E. Miller on May 1, 2022 at 10:45 am

          I was just watching a YouTube video about reforestation In Niger where Black Locust trees were used. When pruning the trees, the branches and leaves were fed to cattle. The comment was that although the leaves were toxic, cattle would self limit the amount to safely eat, but the leaves shouldn’t be fed to horses

  16. […] and another white bloomer, the NATIVE Black Locust is a winner…   […]

  17. […] the best type of wood you can use in your fire pit, black locust is prized firewood. Many people prefer this type of wood over common favorites such as oak or ash […]

  18. Liza Simms on June 12, 2021 at 9:49 am

    This tree is great for farms but maybe not suited to urban lots. I have a few in my pasture and they are easily controlled by normal grazing and mowing, regular pasture maintenance.

  19. M J Hampstead on June 14, 2021 at 1:20 am

    Hi

    I have a self sown grove of locust. They will shortly be razed and will be the site of a drain field.

    What can I do to keep whatever roots are still in the ground from sprouting? This is really important as it can impede the drain field.

    Thanks from Parma MI USA

  20. Dr Jordan Lee on July 14, 2021 at 2:01 pm

    Hi Steve, thank you for praising a useful tree! I am a honeybee farmer. Locust trees are good for bees, as you mentioned.
    I am worried about a trend at greenhouses to sell “seedless” locust trees. That means less helpful to bees. ~sigh~ People can forget that making nature “friendlier” to people can mean harmful to nature.
    I think we can be creative enough to find solutions that benefit people AND nature.

    • Ioana on July 23, 2021 at 5:01 pm

      As a Romanian, I have grown to love late Spring when the Locust trees are in full bloom through the streets of Bucharest. It makes a good “tree well”, or street tree, because the suckers have nowhere to go… And indeed, the honey from these flowers is incredibly fragrant… These days, we have a 10′ tall sapling that has volunteered in our yard at the foot of a tall (80′) Tulip Poplar, with just about 10′ distance between them. Both are close to the house. Do I let it grow, or will it weaken the larger tree, itself a “fast grower”? It is a bit too large to dig out and move.

  21. […] Check with a local Extension agent or other experts to learn more about the availability of black locust lumber in your area. If you can find it, its hardiness makes it a good candidate for your raised beds (source). […]

  22. John Mazur on June 21, 2022 at 9:01 am

    I have straight locust growing everywhere. In Sherburne NY. Varying diameters. How can I prosper from this? Thanks

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