Is Black Locust the Ultimate Permaculture Tree?


You can spot where the old homesteads are in Montana as you will likely find a stand of black locust trees. I’m surprised we don’t see more black locust here as they have to be one of the most useful trees ever.

They are famous in permaculture circles as a “nitrogen fixer.” Another way of looking at this is that they provide free fertilizer to neighboring plants.

They have tiny leaves which create a dappled shade under the tree – perfect for other plants that choose to grow near a black locust. Plus the leaves come out late in the season, allowing time for the sun to warm the soil in the spring. In other words, this tree is excellent at caring for other plants.

The wood from the tree may very well be the best wood that can grow in our area for anything outdoors. Fence posts, patio furniture, sheds, trellises, animal shelters … they can all last for a hundred years without any paint, stain, or other wood preservative – far longer than cedar.



As this video points out, black locust provides excellent bee fodder, grows rapidly, and  even makes excellent tools (isn’t Brian’s hay rake awesome?). Note, because it doesn’t rot quickly, I don’t recommended it for the inside of hugelkultur beds but I have used it for the borders.

When folks ask me about what to use for a raised bed border, I always say “stone.”  And if that is in short supply, I have a long list of what not to use:  railroad ties, treated wood, cedar, black walnut ….  but in this scenario black locust is the mystery jewel.

A gnarled black locust tree dusted with snow.

In fact, because it lasts so long, farmers called it “stone wood.” I use it for my raised beds. We know it contains 4% fungicide by weight so often the concern is whether it is safe for whatever is growing in one’s beds, but the natural fungual component is pretty tightly locked up inside of the wood, keeping the growies happy.

Missoula’s Mark Vander Meer says that black locusts are under-appreciated trees. Yes, they are exotic and invasive though not too invasive here. He shares that they are tougher than hickory (so use the wood when half green, too aged and you won’t be able to drive a nail through it) and, black locust makes great firewood, buring clean and hot.

It is certainly known to have several toxic components that affect the gastrointestinal and nervous systems, which is why concerns over animal safety often accompany this tree. In my experience, if critters have lots of other things to choose from, they will eat that which is best for them so having black locust trees in the area isn’t a huge problem.

Our friends at Inspiration Farm have managed their goats, exposing them to small amounts of the black locust tree leaves, bark and branches, to no ill-effect. This is one of those complicated things where it has been proven to be toxic and at the same time, it has been proven to be an excellent feed source to certain animals. Identical to another legume, alfalfa – alfalfa has been proven to be toxic but is also one of our primary feeds.

I strongly suggest that people collect a handful of black locust seeds and plant them on their land.


Paul Wheaton is is the tyrannical ruler of two on-line communities. One is about permaculture and one is about software engineering. There is even one for Missoula. Paul has written several permaculture articles starting with one on lawn care that he presented at the MUD Project 17 years ago, including articles on raising chickenscast iron and diatomaceous earth. Paul also regularly uploads permaculture videos and permaculture podcasts. In his spare time, Paul has plans for world domination from his hollowed out volcano in the Missoula area, with good submarine access.

See all of Paul’s contributions to Make it Missoula here.