Britain’s cities have served as the epicentre for countless invasions over the years. Landing sites, if you would, where species from far-flung destinations – East Asia, North America and closer to home, in Europe – gain first a toe-hold before beginning their creeping advance across the land. Here, in the city, the wheels of countless vehicles transport seeds, tenacious pioneers breach the walls of their manicured garden cells and unwitting homeowners provide an endless supply of food, sustaining some feral beings on their quest towards colonisation.

Yesterday, I decided to pause and look. To take a moment to seek-out the non-native species with whom I share my street  (a small area of no more than 300m). I must confess, I was quite surprised – many, it seems, find the urban realm much to their liking.


Rising triumphantly between the pavement slabs that line the street adjacent to the fractured glass of the bus stop from which I make my daily commutes, the obnoxious yellow blooms of the day’s first invader add an unseasonal touch of colour at a time when little if anything, should flower. Oxford Ragwort, a native to the lava fields of Sicily, so named for the botanical gardens where the plant was first grown in the 1700s, clearly at home in the cracks and crevices provided by splitting concrete and crumbling wall.

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Oxford Ragwort and Red Valerian growing side by side

So prolific is the ragwort here that it is easily the most frequently encountered ‘wildflower’ on the street, rivalled only by the less widespread yet thriving swaths of Red Valerian – another Mediterranean immigrant – which likewise finds the degrading stonework here to its liking. Both do well here, despite an annual dose of herbicide courtesy of the local council.

The invading botanicals here appear to have organised themselves quite well into some semblance of a natural, tiered community. While ragwort and valerian dominate at ground level, Buddleia prevails at altitude: standing tall in neglected gardens, atop walls, on rooftops and even chimney stacks. The dominant species in the sparse canopy of the street which, brick-breaking tendencies aside, I actually find myself gazing upon fondly. This invader, perhaps more so than the others, providing a boon to insects [and those who enjoy them] throughout the summer months.

While I see Buddleia everywhere I look on my street, some new arrivals are just beginning to gain a toehold. Along the railway lines some 25m from my front door, patches of much-maligned Japanese Knotweed have now appeared. In cracks and crannies on the sunnier side of the street, Trailing Bellflower – a native to the Alps – has begun to creep gradually from garden to garden. Each plant set to paint the stonework here a pleasant blue later in the year. There are others too: a passing glance at the exposed soil at the based of nearby lampost revealing a small, nondescript holly-shaped plant. Not our native Holly at all, in fact, but Oregon Grape – a spiny import from Western North America where, in its natural environment, it forms a dense understory in the shade of towering Douglas Firs. It will find no fir trees here – not that it will be deterred.

Heading to the local park, keen to seek out something, anything, which truly belongs, a piercing shriek and a series of gleeful whistles herald the arrival of another uninvited guest. Sure enough, moments later, a lurid green parakeet emerges atop a budding sycamore. A bird hailing from East Asia, perched in a tree of Eastern European origin looking out across a street laden with arrivals of North America, Italy and China… all in one tiny corner of Britain.

Say what you will about invasive species, they do, in my opinion, deserve some degree of respect for carving out a home in what are often entirely unnatural settings. Some are damaging, some are relatively harmless, but all are interesting.

Written by James Common

Naturalist and nature writer from North-East England, forever learning. Common By Nature is maintained as an outlet for opinion and personal musings associated with the natural world, and as a journal detailing my exploits in the great outdoors. Enjoy!