Sunday, January 24, 2010

Honey Locust Thorns

During the winter, I enjoy seeing things that are hidden by the leaves of summer. One impressive sight is the thorn encrusted trunk of the Honey Locust, Gleditsia triacanthos. Here is a trio of Honey Locust trunks that all sprouted from the same cut stump. The thornless tree grouped with them is a Black Walnut.

This is a tree that really doesn’t want to be hugged. I would guess that a bird nest in the boughs of a Honey Locust would be safe from ground based predators. I can’t imagine anything climbing that thorny trunk. The degree of thorniness varies between trees. Some are practically thornless, while others are fully covered.

This looks like what Prince Charming had to hack his way through to get to Sleeping Beauty. The thorns are very sharp and are often stout enough to penetrate a tire or a hiker’s footwear. Years ago I read an article in an outdoors magazine detailing how to remove a Honey Locust thorn from your hand. There was a lot of detail about killing the pain, keeping the wound clean and using different tools for the extraction, but it never did say why you couldn’t just grab the thorn and pull it out.

A lot of the older thorns have holes that look like they may have been made by something exiting the thorn. I wonder if there might be a borer or some other insect that develops inside the thorn and emerges at maturity. It would really be neat if it was something like an ant that maintained a colony inside the thorn. I may have to open a few thorns this summer and see if I can find out what’s going on.

The newer thorns look to be some kind of modern sculpture. The sharp points are in clear evidence, but the bright color and shiny appearance make the thorns much less menacing.


  1. Steve- I've seen plenty of Gleditsia triacanthos in my wanderings, but these trees might get the prize for the thorniest. What I think is interesting about this species is how there is a theory that the animals that these spines were meant to protect against are now extinct. Although perhaps not, if people are getting skewered too.


  2. My blood ran cold when I saw this blog's title. I was impaled by one of these while wearing soft-soled shoes two summers back. Ow ow ow ow ow! I only wear boots at the back tree line now.

  3. are the thorniest I've ever seen too. You definitely don't want to accidentally walk into that tree!

  4. Steve,
    We have several of these trees on our property in KY and they are getting out of hand. We have animals on our property and they propose as hazard. Is there a way to remove or poison them? Fencing them off is not a solutions as they just spread to other areas.
    Any ideas? Terrie

  5. Hi Terrie. Honey Locust will regrow from cut stumps and from root sprouts, so herbicide is necessary to eliminate them. A variety of effective chemicals are available for Honey Locust treatment. Type used depends on your particular situation. Since chemical names and formulations seem to change yearly, it's best to check the chemical labels to make sure of application times and methods. Here are links to a couple of OSU Extension publications that give some good information on chemicals to control Honey Locust.