Butterfly bush

Buddleja davidii


Photo credit: ©Nina Tallent-Halsell
Butterfly bush – Buddleja davidii
  • B. davidii is a small multi-stemmed tree, displaying a wide range of phenotypes depending in the environment. They are fast growing; depending on the environment, they may grow 0.5m-2m in height annually.
  • They are semi-deciduous, with smaller leaves immediately replacing the shed leaves in autumn. The finely-toothed leaves are opposite,and are generally ovate and shortly petiolate. The tops of the leaves are dark green and free of hair, compared to the paler, hairier underside. The leaves measure up to 20cm long and up to 7cm wide.
  • The flowers appear at the end of the branches and can be to to 30cm long. In the wild, lilac and purple flowers are common; cultivated specimens range from paler colours like yellow and white to darker colours like deep red. The flowers mature from the bottom of each head; each individual flower may last up to 3 days, and the entire head may last for more than 2 weeks. The viable seeds are small, brown and may be smooth or covered with hair. It can also reproduce asexually through stem and root fragments.
  • This is an opportunistic species and can establish in both natural and disturbed areas, and can grow in a wide range of conditions. It may be seen in disturbed areas, such as broken walls or derelict sites, or natural areas, like riparian areas, transport corridors and clear cut forests.

 Flower inflorescence - © Nina Tallent-Halsell

Origin and Worldwide Distribution:
  • It is native to China, but has been introduced to a great number of other countries, where it is considered invasive.
  • Its introduced range includes South Africa, Zambia, Zimbabwe, Malaysia, Czechia, Denmark, Poland, Sweden, Ireland, Greece, the Netherlands, Spain, Portugal, the United Kingdom, the USA, Australia, New Zealand, Brazil, Colombia, Venezuela and Ecuador.

Potential or Known Impacts:
  • It forms monocultures and can prevent the growth and regeneration of native species. It may displace primary colonisers across different habitats.

Buddlieja encroachment - © Nina Tallent-Halsell

  • It can reproduce via viable seeds, and through stem and root fragments. The seeds may be viable for up to 2.5 years, but is generally a short lived seed bank. It can also shade out ground flora.
  • In Europe, transport routes may be impacted as this species may readily colonise these routes. Visibility may be impacted due to its height.
  • Native pollinators may be more drawn to this species compared to native species, which may lead to a decline in native species.

How did it/could it get here?
  • It was introduced as an ornamental species, that had a benefit as a food source for pollinators. It has readily escaped into the wild.

Is it found in Northern Ireland?
  • It is found in Northern Ireland.

You can help by reporting any sightings: @ the Centre for Environmental Data & Recording (CEDaR) - Or via the iRecord App.
Methods for Prevention:
  • Report any sightings.
  • Do not plant this species – plant native species instead.
  • Do not take or give cuttings from wild or cultivated plants.
  • Deadhead specimens that you are removing. Dispose with care as it can rapidly germinate and grow in different habitats.
  • Know what you are growing.
  • Never collect plants from the wild.
  • Safely dispose of plants and growing media.
For further queries, you can contact the Invasive Non Native Species (INNS) Team in the Northern Ireland Environment Agency on 028 9056 9558 or Email: invasivespecies@daera-ni.gov.uk  

Species Related Files:

Invasive Species Ireland

Invasive Species Ireland