More on the Japanese Barberry-Lyme Tick Connection

A post of mine from April 2011 describes research connecting the non-native, invasive shrub Japanese barberry (Berberis thunbergii) and Lyme disease-carrying ticks.  Basically, scientists at the Connecticut Agricultural Experiment Station in New Haven found that stands of Japanese barberry create ideal growing conditions for Lyme ticks.

You can also read about the scientists’ similar, previously reported research in an April 2010 post.

To learn more about this research and control methods being used on conservation lands read the  well-done report Scientists link invasive barberry to Lyme disease in The Day. Read this article!

A sidebar to the article notes the high tick populations seen so far this year in Connecticut. Unfortunately, more barberry leads to more ticks. More ticks means higher risk for Lyme disease.


Do you need a better reason to not plant Japanese barberry and control the barberry that’s invading Connecticut woodlands?

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8 comments for “More on the Japanese Barberry-Lyme Tick Connection

  1. June 20, 2011 at 9:26 pm

    Very interesting! I have a few barberry plants, so I will have to be careful. I wonder what it is about those plants that attract the ticks. Thanks for the info…

    • joenesgarden
      June 21, 2011 at 6:43 am

      Sage Butterfly,
      Barberry does not necessarily attract ticks. When growing in groups, barberry creates an ideal environment for ticks. Barberry leafs out early, grows low to the ground and is not browsed by deer. This establishes a moist environment in which ticks thrive. Mice also find cover under barberry. Ticks use mice for one stage of their growth cycle. Ticks then travel up the barberry stems and hitch a ride with passing mammals – often deer as they stroll by. This allows ticks to complete another part of their life cycle. All these factors together help increase the tick population. Add on that Japanese barberry produces berries, and birds eat the berries then deposit the undigested seeds, and you have a fast spreading – now invasive – shrub. Since barberry spreads rapidly, is a bear to remove, and is not browsed by deer it has taken over large sections of Connecticut’s woodlands. These large barberry stands create an ideal environment for ticks … and the circle continues. It appears that controlling barberry – its availability and distribution – and managing existing barberry stands is one method to slow or stop the cycle in specific locations. Some barberry cultivars produce fewer seeds and are, theoretically, less likely to spread. But as gardeners we know that seeds sprout and spread, often in ways we don’t foresee. So why take the chance of adding to the problem by planting or maintaining barberry shrubs in ornamental beds – unless, of course, one it TOTALLY committed to removing and destroying all barberry seeds from these shrubs.

  2. June 21, 2011 at 7:36 pm

    Joene, Thanks for posting the link to that article. While there may be a rise in ticks this year, I think we can expect even more in the coming year. Supposedly 2 years after a mast year of acorns (if I’m remembering correctly 2010 was a mast year) we should see an explosion of ticks. More acorns = more small mammals survivng the winter & breeding=more ticks the following year. While this is only anecdotal evidence, I haven’t seen so many chipmunks in my garden in years.

    • joenesgarden
      June 21, 2011 at 9:10 pm

      Debbie, it’s not just chipmunks. I’ve had a lot of voles in previous years, but this year beats all. I’ve heard more people complaining of voles, chipmunks, squirrels, mice … essentially rodents … than ever before. I expect … hope … that the owl population is booming along with the rodents. I’ve heard a lot more nighttime owl activity this year.

  3. June 21, 2011 at 11:38 pm

    My evergreen holly shrubs are incredibly tick infested. Every time I weed anywhere near them I am covered in ticks. Same ideal growing conditions as the barberries — the hollies have foliage all year and it is dense and it harbors mice and other critters. Unlike the barberries the hollies are not spreading in the woods, but where I have planted them has become a no-go zone for me. I had a horrendous bout of Lyme disease in ’08, with facial paralysis and fever and terrible joint pain, so I am hyper about the ticks now. And there they are, in huge populations in the very plantings I put in!

    • joenesgarden
      June 22, 2011 at 8:07 am

      Great point. I have also noticed high tick populations around plantings with evergreen shrubs but hadn’t really thought about why. Thanks for making the connection.

  4. June 27, 2011 at 7:14 pm

    I saw a tick for the first time just a couple of weeks ago. (I”m from Chicago. No ticks, no deer, just mosquitoes.) I couldn’t believe how tiny they are. I am glad two of my barberries went kaput. I returned those and the other four that had not gone kaput. Some of the comments in The Day were disturbing. People don’t want to hear what they don’t want to hear. I just want to be a more responsible gardener and am therefore grateful for bloggers such as yourself and Laurrie and so many others who keep me in line. Good post!

    • joenesgarden
      June 27, 2011 at 9:35 pm

      Wendy, thank you for such a nice comment. How lucky to not have deer foraging your gardens!

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