Country diary: rosebay willowherb, the spirited pioneer

Country diary: rosebay willowherb, the spirited pioneer

The Chevin, Otley, West Yorkshire: In North America it is commonly known as fireweed, for the startling swaths of it that quickly colonise the charred wake of wildfires.

In the subdued green-grey light of an overcast August, it is hard not to feel like the best is behind us. The swifts have gone, and the intoxicating Mediterranean brilliance of just a few weeks ago already seems to belong to a different year. A verge that thrilled me in May as a festival of confetti-coloured flowers is now just a limp tangle of grass. Summer is still here, but there is a sense that the party is winding down, and the comedown is beginning.

But on the top of the Chevin, scattered over the once-quarried heathland like a volley of bursting shells, there is a colour more incendiary than anything produced even by the first rush of spring: the explosive purple-pink of rosebay willowherb. When chinks of evening sunlight escape through the clouds and land on the clustered, flowering spires, the resulting blazes are almost too much for the eye. Contrasted with the deep, almost gloomy greens around it, and with a hint of autumn in the air, the audacious brightness is the very stuff of hope.

Rosebay willowherb (Chamerion angustifolium) is a pioneer species, having evolved to quickly reclaim burned or disturbed terrain. In North America it is commonly known as fireweed, for the startling swaths of it that quickly colonise the charred wake of wildfires. It is seeded by destruction; but the origin of that destruction can be human, too.

Once rare in England, it spread as the railways ate through the land. During the second world war huge drifts of it sprung up in the craters and wreckage of the capital. In 1944, the American reporter Lewis Gannet wrote: “London, paradoxically, is the gayest where she has been the most blitzed.” He saw “great meadows” of the flower in Lambeth, and noted that behind Westminster Abbey “bits of it are high up where second-storey fireplaces still cling to the hanging walls”.

In Alaska, the spires are thought to measure the season; the blooming flowers progress up the stem, and when they reach the top the plant starts to go to seed. The seeds then drift away on ghostly strands; the fireweed burns out, goes up in smoke, and the summer is spent.