Butterbur Sweet-coltsfoot

Fact SheetPetasites hybridus

Images of this species:

Common look-alikes:

Identification

Appearance

Herbaceous perennial resembling rhubarb favors moist to wet areas. Roots have a tuberous base with extensive, fleshy creeping rhizomes. Rhizomes are blackish on the outside with white interiors.

Foilage

Large, heart shaped leaves and thick fleshy stalks, span up to 3 feet across. Plants resemble rhubarb. Leaves do not fully emerge until after flowering has occurred. 

Flowers

Pinkish flower stalks, composed of bundles of tiny pink radial flowers, emerge from underground in early spring. Blooming occurs before the leaves fully emerge and expand. Male and female flowers typically appear on different spikes.

Fruit

Seeds are attached to feathery pappus (plumes of fine white bristles). In some conditions, seeds are sterile.

Biology

Ecological Threat

Invades wetlands, forests, forest edges, bogs, marshes, and other semi-shaded moist areas. It grows quickly and shades out native species.

Origin

Native to Europe.

Habitat

Meadows, fields, disturbed areas, riverbanks, lakeshore

Life Cycle

Blooming occurs in spring before full leaf out. Male and female flowers typically appear on different spikes.

Management Options

This species is considered a watch list species. 

Treatment Concerns: 

  • There is relatively little known about the behavior and treatment of this species in North America. What is presented is what is currently known for management as of June 2022. Any recommendations below may be out of date, as new data continues to emerge on how to best manage for this species.  
  • The primary method of spread is by the rhizomes and rhizome fragments, so any treatment should take care to reduce spread.  
  • Rhizomes and portions of roots system not removed can re-sprout. 

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. 
  • 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.   
  • Be careful not to damage or kill nearby desirable plants when conducting management work.  
  • The label is the law for all pesticides (economic poisons) and uses.  
  • 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. 
  • Management options listed below are representative of research by institutions like the Midwest Invasive Species Information Network, Wisconsin Department of Natural Resources, and the Royal Horticultural Society.   
  • Here are additional guidance documents on best management practices for butterbur. 
  • Midwest Invasive Species Information Network 
  • Wisconsin Department of Natural Resources 
  • Royal Horticultural Society 
Summary of Mechanical, Chemical and Biocontrol Treatment Options
  • Digging or hand pulling the plant and it's entire root system, and monitoring for re-sprouts are current recommendations from a few U.S. based management institutions. 
  • Application of a non-specific herbicide to the leaves is a current recommendation from a few U.S. based management institutions. 
  • Related species with similar characteristics and methods of spread have been initially found to be easily treatable with foliar application of non-specific herbicide to leaves or by string trimming aboveground vegetation, though effectiveness is still not determined (2018 study in Scotland).  
  • In agricultural settings in the U.K. where it is a locally-evolved pest, this species has been managed by string trimming, mowing, and foliar application of non-specific herbicide to leaves. 
  • There are currently no known biocontrol agents for butterbur.   

 

 

Citations

Photo Credit

5382461, William M. Ciesla, Forest Health Management International, Bugwood.org

5382462, William M. Ciesla, Forest Health Management International, Bugwood.org

Information Credit

Wisconsin Department of Natural Resources, Butterbur sweet-coltsfoot

GoBotany, Butterbur sweet-coltsfoot

Midwest Invasive Species Information Network 

Royal Horticultural Society