Picture the urban scene. The chimney with a plume of bush, not smoke. The stuttering guttering, become plant container. The rubble filled wasteland temporarily knotted with growth. The brick rail bridge decked with foliage and flowers. Let us celebrate buddleja’s brazen ways – the way it rampages through unloved urban areas and clings to the side of buildings.
Of course some people hate it. They declare it an invasive weed and call for a cull. In natural areas it can strangle out native species and should be controlled, but in concrete deserts surely we should praise its tenacity and the rich nectars it provides to urban insects. Tamed in the garden it can be a striking butterfly magnet.
Professor Peter Houghton has been studying buddleja for 30 years, and has spent many an afternoon on a railway siding digging up its peppery smelling roots. He once had a freezer full of root samples that, when tested, were revealed to have anti-fungal properties. This could be a way that buddleja protects itself against attack from creatures in the soil. It’s a plant he continues to be fascinated by, but no longer has in his garden or his freezer.
The manmade urban landscape often mimics buddleja’s natural one of rocky mountain tops and dry shingle. Peter explains that “it occupies an ecological niche in tolerating the high levels of calcium found in mortar. Buddleja loves well drained soil and is good at conserving water. The hairs on the underside of the leaves must play a part here, covering the stomata and cutting down evaporation.”
Self-seeding Buddleja davidii was brought to the UK from China in the 1890s. It became widespread as a weed in Britain after World War Two, rushing like wild fire through freshly exposed bomb sites and reveling in all that exposed mortar and rubble. It’s now seen growing with abandon in towns and cities across the UK, and beyond.
Peter’s lifelong investigations include looking into buddleja’s use in traditional medicine. The leaves have been used as a poultice for wound healing in Eastern Asia, South Africa, South America and Mexico. An infusion of the flowers of Buddleja officinalis, which blooms in January, is used as an eye-wash and to reduce inflammation in Chinese medicine. It can be found growing in the Chelsea Physic Garden, which showcases medicinal plants from around the world.
And what of Buddleja davidii’s bad reputation? “It is like the urban fox – it’s nice to have something wild in the city but it can be annoying too” says Peter. “You have to keep it under control in gardens, but it’s nice to see a wasteland covered in it. It’s certainly one of the most attractive weeds we’ve got, and one of the only ones that’s a bush.”
© Helen Babbs / The Guardian 2012