Buddleja davidii is a shade-intolerant woody weed from China, which, with small wind-dispersed seeds, rapidly colonises bare or disturbed sites. It is cultivated for ornamental purposes for its pretty flowers and ability to attract butterflies.

It often takes hold in disturbed areas or open woodlands and has proven to be one of the worst weeds to forestry managers in New Zealand. Approval for release of a biological control agent, a leaf-chewing beetle Cleopus japonicus, has recently been given in New Zealand.