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Eastern Cottonwoods & European Honey Bees


One species of tree you might encounter if you’re in a floodplain is the Eastern Cottonwood (Populus deltoids), a member of the Willow family and the Poplar genus. Because it can tolerate flooding, it often grows near river banks and disturbed wet areas. The buds of Eastern Cottonwood are large and somewhat sticky, due to the resin that they contain. Resin exudes from the buds during the fall as well as the spring, and is evident even in winter when you see it frozen in droplets on the buds (see photo). In trees, resin serves to seal wounds and defend against bacteria, fungi and insects.

European Honey Bees discovered that the properties of cottonwood resin which benefitted cottonwood trees could also benefit them. They collect the resin from the outside of Eastern Cottonwood buds, mix it with wax and apply it to the walls of their nest cavity. This “bee glue” is referred to as propolis, and, as it turns out, serves as an antimicrobial barrier as well as a sealant. Various bacteria, fungi and other harmful microbes are kept at bay by the resin contained in propolis. It also directly reduces two diseases of Honey Bees, chalkbrood and American foulbrood.

Interestingly, if a mouse or small rodent happens to die inside a hive, and the bees can’t remove it through the hive entrance, they often seal the carcass inside an envelope of propolis.  This prevents the hive from being affected by the mouse’s decomposition.

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10 responses

  1. Marcy Neville

    I believe the common name for this cottonwood, Balm of Gilead, comes from the healing quality of this resin. thnx!


    March 8, 2017 at 7:11 am

  2. Brenda M

    Mary, this is so fascinating! Thank you! B

    March 8, 2017 at 7:49 am

  3. Alice Pratt

    Bees are so amazing. My daughter and her spouse have bees, the honey is so delicious and she makes lipbalms with the wax added.

    March 8, 2017 at 8:06 am

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  5. Libby Hillhouse

    Thanks! I reposted on the Northeast Kingdom Beekeeper’s FB page.

    March 8, 2017 at 8:53 am

  6. Kathryn

    Amazing! you always come up with such interesting information!

    March 8, 2017 at 9:07 am

  7. Rita Ferrarar

    This is such a rewarding blog! Love today’s entry on Eastern cottonwood resin and the use European bees have made of it.

    March 8, 2017 at 10:01 am

  8. Fascinating!

    March 8, 2017 at 6:24 pm

  9. Jean Harrison

    “Deltoids” are muscles, “deltoides” is the species name. I didn’t know this resin was an ingredient of propolis. You score again with fascinating facts of nature.

    March 8, 2017 at 11:55 pm

  10. How fascinating! We will be getting our first bees in a couple weeks and I just made several batches of balm of Gilead! I didn’t realize bees loved it as much as I do. Thank you for the post.

    April 10, 2017 at 11:20 pm

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