Common Comfrey

Native

Common Comfrey originates from Europe and parts of Asia, where it has been cultivated since 400 BC as a garden ornamental and a medicinal herb. It was introduced to North America in the 1600s and is still used today to treat skin irritations, cuts, sprains, and swelling; however, it is carcinogenic when ingested.

Common Comfrey can be found growing in shady areas such as meadows and woods, especially near streams and rivers. It grows best in nutrient-rich soils, but can also tolerate drought conditions and disturbed soils.

Common Comfrey is currently found throughout the Sea to Sky Corridor, so the best approach to controlling its spread is by PREVENTION.

 

Learn to identify Common Comfrey: use the images presented on this profile page to learn how to identify Common Comfrey.

What to do if you spot it: You can report any Common Comfrey sightings by clicking here.

DO:

• Regularly monitor properties for weed infestations.
• Ensure soil and gravel are uncontaminated before transport.
• Check wildflower mixes to ensure that they do not contain Common Comfrey.
• Minimize soil disturbances (e.g. use grazing plans that prevent soil exposure from overgrazing), and use seed mixes with dense, early colonization (e.g. alfalfa or barely) to re-vegetate exposed soil and resist invasion.
• Ensure that plants are disposed of in a garbage bag if found in floral arrangements to prevent seeds from spreading.

DO NOT:

• Unload, park, or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles, or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
• Plant Common Comfrey in a garden, no matter how well-contained its enclosure may seem.
• Move soil that has been contaminated with Common Comfrey.
• Do NOT compost!

Control

Mechanical

• Once established, Common Comfrey can be very difficult to remove due to its large taproot.
• If digging out, ensure that as much of the taproot is removed as possible because new plants will form from any fragments left behind.
• Removing during hot, dry weather will aid in killing off remaining root fragments.
• Mowing plants before they go to seed in the spring can prevent spread.

Chemical

• Broadleaf herbicides provide optimal control; a higher rate of herbicide will be necessary as the plant grows.
• Using a surfactant will increase coverage and ensure that herbicide penetrates the plant, as hairy bristles on the stem make it difficult.
• Triclopyr and clopyralid have proven effective for this plant, as has picloram, but the latter is not suitable for wet, coastal soils.
• We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial, and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.

Cultural

• Planting competitive, native plants in areas where Common Comfrey has been removed will help to prevent weed occurrence.

Biological

• There are currently no biocontrol for Common Comfrey.