Plantwatch: Wildflowers lose out twice from nitrogen pollution | Environment

Nitrogen pollution in the air is devastating for many sensitive wild plants, which is why so much of the countryside is becoming a vast carpet of nettles, hogweed, hemlock and other rampant vegetation that feasts on nitrogen. In many places, these are running out of control.

Much has been written about the damage to human health from nitrogen oxides given off by traffic, but the damage to sensitive plants has gone largely unnoticed. Excessive nitrogen also comes from ammonia from fertilisers and manures, with much of the countryside awash with nitrates running off farmland.

More than a third of Britain’s wild flowering plants need low levels of nutrients in the soil, and they are suffering from too much nitrogen raining down from the atmosphere. That onslaught is having a devastating effect on 90% of sensitive plant habitats in England and Wales, such as woodlands, grasslands, heaths and bogs, according to the charity Plantlife. And in some wild areas, nitrogen-guzzling plants such as nettles have run riot and swamped the natural wild plants.

Nitrogen pollution can come directly from the air or be washed down in rain. It is absorbed into the soil, creates acidic conditions and damages sensitive plants. More than two thirds of our wild flowers such as harebell and betony need low or medium levels of nitrogen. And it is only robust species, such as nettle, that can thrive in this flood of nitrogen.