There was an article in EntomologyToday recently about new data which shows Japanese Barberry (Berberis thunbergii) harbors the Blacklegged Tick (Ixodes scapularis) which carries Lyme Disease. I have a good friend who suffers from the ravages of Lyme Disease, and I’ve other friends who also have been affected by this horrible disease, so I thought this would be a good story to investigate.
A study conducted by a team led by Scott C Williams, PhD at the Connecticut Agricultural Experiment Station concluded that clearing away the growth of Japanese Barberry every five years reduced tick abundance to a level nearly equal to the levels of non-barberry plots. The tick has a two-year life cycle, so the reduction doesn’t occur until the third year after the growth of the barberry has been removed. But then it lasts through year five. So by maintaining a five-year management cycle, the near elimination of this tick should be achievable.
Although Williams work was limited to Japanese Barberry, he suggests the same type of management might be warranted for other plants such as ferns, burning bush or huckleberry — all of which provide the same type of “humid microclimate” which favors Blacklegged Tick survival. In addition, a study conducted by Brian F Allan et al concludes Amur honeysuckle (Lonicera maackii) also harbors the Blacklegged Tick.
Non-Native Japanese Barberry (Berberis thunbergii)
Japanese Barberry was introduced from Japan in the late 1800s because it was deer resistant due to its thorny exterior and because it thrives in most ecosystems. Unfortunately, besides its relationship with the Blacklegged Tick, it also plays well with non-native earthworms which leave the soil depleted for native plants, but adaptable more non-native Japanese Barberry.
White-Footed Deer Mice and other rodents are the principal carrier of the Lyme Disease tick because they nest under this barberry. However, even though deer do not eat the shrub, ticks will often hitch a ride as the deer walk by and that is why deer are blamed for spreading Lyme Disease.
A Watch-Out!
According to the Midwest Invasive Plant List, Japanese Barberry is listed as invasive in all the Midwestern states except Missouri. USDA lists it as invasive in Connecticut and Massachusetts, also.
Don’t be fooled into purchasing “sterile” species of non-native barberry. It is generally impossible to guarantee a plant is 100% sterile.
Native Alternatives to Non-Native Barberry
There are many lovely native shrubs to choose in place of the non-native barberry. How about trying Winterberry (Ilex verticillata), Golden Currant (Ribes aureum), Chokeberry (Aronia spp), Virginia Sweetspire (Itea virginica), New Jersey Tea (Ceanothus americanus) or American Holly (Ilex opaca) — just to name a few. Find more alternatives in Charlotte Adelman’s book Midwestern Native Shrubs and Trees: gardening alternatives to nonnative species.
Here’s a good fact sheet on Japanese Barberry by the Michigan Department of Natural Resources.
According to the Midwest Invasive Plant List, Japanese Barberry is listed as invasive in all the Midwestern states except Missouri. https://www.mipn.org/plantlist/ USDA lists it as invasive in Connecticut and Massachusetts, also. https://plants.usda.gov/core/profile?symbol=BETH.
I think the same applies to the invasive Asiatic honeysuckle shrubs.
You’re correct, Quita. I found a study in the US National Library of Medicine PMC website that concurs. Amur honeysuckle (Lonicera maackii) not only hosts the Blacklegged tick which causes Lyme Disease, it also hosts the Lone Star Tick (Amblyomma americanum) which carries ehrlichiosis. In this instance, White-Tailed Deer are thought to be the primary carriers since they often bed down in areas infested with honeysuckle, as well as browse.
Question about Huckleberry – it shows as being native to
most of the U.S. here:
https://plants.usda.gov/core/profile?symbol=GAYLU. Thanks! – Toni, Habitat Ambassador, Nature Scoop
Hi! Toni — Interesting question. It took me awhile to track down where I got that info from, but I believe I must have made an assumption about the plants I mentioned in that sentence being non-native. The original articles don’t categorize them.
I did find, however, that huckleberry is a member of the Ericaceae family which includes both of these genus, as well as the non-native fruits blueberry and cranberry:
https://plants.usda.gov/plantguide/pdf/cs_vaov2.pdf Evergreen Huckleberry (Vaccinium ovatum) native to British Columbia south into California.
https://plants.usda.gov/core/profile?symbol=GAYLU Gaylussacia baccata (Black Huckleberry) native to eastern USA into Canada.
And both grow to be very dense shrubs, hence the climate conducive to the breeding of the Lyme Disease tick.
The article on Japanese Barberry has been corrected to include the information discussed in the comments above.