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Butterfly bush

Butterfly bush

Butterfly bush

(Buddleja davidii)

Priority: -  Control

Tags: Terrestrial

Identification and Reproduction

Identification:

  • Butterfly bush is a deciduous to semi-evergreen shrub. It can grow to 5 m tall with over-arching branches. 
  • Young stems appear green but with maturity will develop into a grey-brown. 
  • Leaves are arranged oppositely and are slightly fuzzy and serrated. They are lance shaped and edges are serrated. Leaves can grow upto 25 cm long.

 

  • Distinct showy flowers are clusted to form an upright or drooping spike-like shape. Butterfly bush flowers can bloom to be a range of purple. 

Reproduction:

  • Butterfly bush primarily reproduces via seeds. Seeds are mainly dispersed by wind during dry days, but they can also spread by water-dispersal (flowing through lakes and rivers). Cars are also capable to produce enough air movement for wind dispersal.
  • Germination rates of seeds can exceed 80%.
  • Butterfly bush can produce asexually from plant parts.



Habitat & Ecology

Frequently found on disturbed areas ranging from light shade to full sun. This plant can also withstand drought and low-nutrient sites. 

Impacts

Ecological: 

  • Outcompetes native species and may alter riparian habitats.
  • By displacing native plants this decreases the biodiversity and habitat for butterflies.
  • Butterfly bush flowers may offer native butterflies a nectar source but unfortunately leaves do not offer catepillars a proper food source. Therefore, this plant disrupts the butterfly life cycle and negatively impacts native vegetation and wildlife.

Management

Mechanical/Manual Control: 

  • Remove seed capsule before they ripen and produce seeds. 
  • Remove larger bushes by cutting the plant at the base.
  • Dig up the stump if possible, or cover it with a thick plastic bag or mulch to prevent regeneration.
  • Be sure to remove new shoots and stems to reduce re-establishment. 

Chemical Control: 

  • Once butterfly bush has been cut, apply herbicide treatment to the cut base. A combination of mechanical and chemical control will prevent regrowth. 
  • Please follow all product and chemical labels prior to application. 

For alternative planting options to butterfly bush download the ISCBC's Grow Me Instead brochure (pg. 13 and 14).

Resources

For more control methods check out King County's page on Butterfly bush here. Note that this is a US site and Canadian guidelines and regulations may difffer. Please carefully read chemcial labels prior to use. 

Header photo (Ikai).