This species is Quarantined: Class B Noxious Weed  

Treatment Concerns: 

• Japanese barberry “leafs out” very early compared to most native vegetation, thus making them easy to detect in early spring.  
• Other helpful indicators to look for are the yellow-colored inner bark and roots. 
• Thorns are sharp and irritation may occur at puncture sites. Use caution and wear gloves when handling this plant. 
• Because of the high risk of spread by seeds, treatments are most effective before the plants go to seed. 
• Seeds can persist for a few years in the seedbank, so it is beneficial to prevent the plant from setting seed. 
• Japanese barberry biomass seems to increase the amount of nitrogen in the soil, which encourages new barberry growth and inhibits that of other plants. There is also a correlation between Japanese barberry, soil nitrification, and non-native earthworms 
• Thorns are sharp, made of silicate, and irritation may occur at puncture sites. Use caution and wear gloves when handling this plant  
• Japanese barberry has been implicated in the spread of Lyme disease because of the habitat it creates for mice and ticks, who are vectors for the bacteria that causes Lyme disease.  
• In places with high deer pressure, locally evolved plants are often replaced by Japanese barberry. 

General Guidance

• Most methodologies alone will not suffice and should be part of an integrated pest management plan.  
• Which methods you choose also depend on the purpose of control: eradication (removal of all plants, plant parts, and seed bank), or containment (reducing seed production, reducing spread, reducing growth, removing individual plants near site of concern).  
• All action promotes disturbance - mechanical, chemical, and even just doing nothing. Our work is in figuring out how to minimize disturbance and maximize positive benefits. 
• The intent of mechanical or chemical treatment is to kill target plants. 
• Management options listed below are representative of research by institutions like The Nature Conservancy, the Michigan Department of Natural Resources, the Minnesota Department of Agriculture, the US Forest Service, and PennState Extension.   
• Here are additional guidance documents on best management practices for Japanese barberry. 
• PennState Extension Resource on Japanese Barberry 
• US Forest Service Fire Effects Information System Report on Japanese Barberry 
• Michigan Department of Natural Resources Best Control Practices for Japanese Barberry 
• Minnesota Department of Agriculture Summary on Japanese Barberry 

Summary of Mechanical Treatment Options 

• Mechanical treatment can sometimes cause greater disturbance than if the site was left alone or if another treatment option was utilized. 
• If pulling or digging, remember that soil disturbance can encourage growth from seed bank.
• It is beneficial to remove plants before they begin fruiting later in the growing season. 
• Portions of roots system not removed can re-sprout.  

 

Summary of Chemical Treatment Options

• Be careful not to damage or kill nearby desirable plants when conducting management work.  
• Always read and follow pesticide label directions. Application of pesticides may require a certification from the Agency of Agriculture, Food and Markets. The Agency website provides information on what applicator certification is needed.
• If a treatment for a specific species isn’t listed on a given product, don’t use it. 
• Product labels may require you to check Endangered Species Protection Bulletins. Learn more about protection bulletins here.  
• Understand the risk of, and how to avoid, drift.  
• The timing of some chemical treatments may overlap with when certain plants are flowering, and, in order to protect pollinators, herbicides should not be applied when plants are flowering. To mitigate the risk, consider utilizing an integrated pest management plan, such as cutting the plants to set back flowering time, and then applying pesticides in the lowest effective volume. 
• Chemical treatments pose a risk to plants, animals, and humans, but can be used in ways that greatly reduce this risk, and provide a solution to otherwise hopeless scenarios. 
• For questions regarding the appropriate chemical to use for a particular situation, or general information on pesticide safety, ingredients, and more, contact the Vermont Agency of Agriculture, Food & Markets’ Pesticide Program.  
• For questions about certification and continuing education credit opportunities, contact the Vermont Agency of Agriculture, Food & Markets’ Pesticide Program.  
• For questions about additional training opportunities, contact the UVM Extension Pesticide Safety Education Program.  
• Special permits are required to apply herbicides in a wetland. Contact Vermont Department of Environmental Conservation’s Wetlands Section for more information.  
• Herbicides cannot be applied within 200 feet of a Public Water Source Protection Area unless the Water Supply Division is notified. Call 1-800-823-6500 for more information. Similar requirements may be in place for proximity to private water sources.  
• Forests that are certified organic or adjacent to organically certified agricultural lands may carry restrictions regarding chemical application. Check with the Northeast Organic Farming Agency of Vermont for more information.  
• The National Pesticide Information Center provides objective, science-based information about pesticides. Check out their website for more information or call 1-800-858-7378. 

Biocontrol

• There are no formal biocontrols for Japanese barberry. A North American moth (Coryphista meadii) has been noted as causing extensive defoliation of Japanese barberry in Michigan, but more needs to be learned to know if it could be considered an effective biocontrol.