Japanese Barberry Control Workshop Review

Jeff Ward, Chief Forester CT Ag. Exp. Station (CAES) and
wearing white ball cap with plaid-flannel at left,
introduces the topics that will be discussed during the workshop.

Yesterday was a great day to spend some time in the woods with a few experts to learn about how to control Japanese Barberry (Berberis thunbergii) in forest ecosystems.  A total of 32 people attended the workshop, some traveling from a far distance while most were from nearby communities.  Participants included natural resource professionals, land trust stewards, students, and other concerned citizens who manage forested property that is affected by Japanese Barberry.  Japanese Barberry is an invasive exotic shrub that forms dense stands under forest canopies.  Participants observed how these dense stands encourage the density of black-legged ticks, a.k.a. deer tick, (Ixodes scapularis) that are infected with the spirochete that causes Lyme Disease (Borellia burgdorferii).  The investigators have also found that dense Japanese Barberry stands may also influence drinking water quality by the plant's ability to increase nitrification and decrease the leaf litter layer.  Nitrification is a process of adding nitrogen to the soil and a healthy leaf litter layer discourages soil erosion.  The lack of leaf litter increases erosion thereby adding more nitrogen to the water supply, this in turn encourages plankton/algal blooms and other aquatic plant outbreaks.  Japanese Barberry stands have also been associated with lower native tree regeneration, fewer herbaceous plant cover (wildflowers), and increased earthworm densities.

I'm sure most of you understand that there is a problem when anything negatively 

influences native trees and plants, but earthworms!  

What's wrong with earthworms?!  

Earthworms are not native to southern New England soils because our landscape was covered by glaciers only 15,000 years ago and these 1 mile thick ice blocks prevented earthworms from colonizing our soils.  Although earthworms might be considered a positive thing in your garden, they are not a good thing in forests.  Earthworms consume the leaf litter layer at an astonishing rate, which as you already know the lack of a healthy leaf litter layer encourages soil erosion.  This workshop was a real lesson in forest ecology!

The principle investigators of this project are Jeff Ward (CAES), Scott Williams (CAES), Thomas Worthley (UCONN Coop. Ext.), and J. P. Barskey (CAES).  They have discovered that managing Japanese Barberry is at least a two-step procedure.  First, the healthy barberry shrub needs to be treated with herbicide, prescribed burning, propane torch, or is cut down with a mechanical method.  After the plant sends up new shoots the following growing season, a second treatment is required by using a propane torch or herbicide.  Safety equipment and considerations, costs of equipment, materials, and labor were also discussed.  Further evidence was provided demonstrating that infected tick density decreases after these treatments are applied.  As well as, evidence that showed how Japanese Barberry responded if the second treatment was not applied, it returns with gusto!

In the following images you can see the various methods that were demonstrated by Mike Short (CAES Technician) during this workshop, but also notice that the orange-red hue in the forest understory, all of this is Japanese Barberry!

Walk behind self propelled brush mower.

Brush Saw

Star brush blade on a brush saw.

Yellow heart wood of a mulched Japanese Barberry shrub.

Jeff Ward demonstrates the use of a propane torch burning Japanese Barberry clumps to kill buds.