Buddleia, commonly known as the butterfly bush, is admired for its vibrant flowers and ability to attract pollinators, but experts warn it poses a serious threat to UK homes and gardens due to its invasive nature.
This fast-growing shrub can reach heights of up to 15 feet and spreads by producing thousands of tiny seeds that easily colonize cracks in walls, roofs, gutters, and foundations, causing structural damage comparable to that of Japanese knotweed.
Unlike knotweed, which requires roots in the ground to spread, buddleia seeds can germinate in hard-to-reach places such as window sills and building crevices, making it particularly difficult to control.
Its fibrous root system and woody stems can force apart mortar and bricks, leading to costly repairs estimated at around £1 million annually across the UK.
Despite its invasive tendencies, buddleia is not currently listed as a controlled species under UK law, meaning it remains legal to plant in gardens.
However, environmental specialists urge homeowners to monitor and manage the plant carefully, especially in neglected or unmanaged areas, to prevent it from overtaking native vegetation and damaging property.
While buddleia provides summer nectar for butterflies, its aggressive spread threatens biodiversity by outcompeting native plants essential for butterfly larvae and other wildlife.
Removal often requires professional intervention, including herbicide treatment or full excavation, to eradicate the plant and prevent regrowth.
Gardeners are advised to remove seed heads after flowering to reduce spread and to consider alternative native plants that support local ecosystems without the risk of structural damage.
