Scurvy Grass

After revelations that a bumper crop of dandelions is emerging alongside Britain's highways, scientists have warned that the summer plant is under threat from a foreign invader... a plant which thrives on road salt.

Record amounts of grit were spread on UK highways this winter and that has given an added boost to "Danish Scurvy Grass" which is spreading like wildfire across the UK. The saltmarsh plant is thought to have arrived in the UK as seeds carried by ships arriving English ports in the middle ages.

For two centuries it remained confined to coastal areas but thanks to the advent of major road gritting operations in the 1970s it began to spread and has now become rampant. Research suggests that the plant, with its tiny white flowers, is spreading along roadsides at a rate equivalent to one metre every 12 minutes.

And the reason for the marauding advance of the hardy weed is that thrives on the high levels of salt created by winter road gritting operations. Combined with the stone ballast used for drainage on Britain's major highways, it creates the perfect recreation of its native cliff-top habitat.

Drivers will notice Danish Scurvy Grass in bloom throughout the spring as a 'white ribbon' of flowers adorning verges across the country. Unnoticeable throughout most of the year, the invader - used by seafarers in the Middle Ages as a cure for scurvy - is blooming as a carpet of white.

It is through the seeds of the grass, botanical name Cochlearia Danica, which are being carried in the tyre treads of cars.

Botanists says that as more diligent council road maintenance has provided the palnt - latin name "Cochlearia Danica" - with a ribon of salty habitat along the side of roads served by gritting trucks in icy weather.

A study in land-locked Worcestershire found it had gone from a rarity to being present on the majority of the county's A roads.

Dr Mark Spencer, curator of the National History Museum's British and European Herbarium, said salting of roads and the effect of traffic flow whizzing by had helped its onward march.

Dr Spencer said: "No-one quite knows exactly where it started its inland spread but once it gained a foothold on motorways it has easily moved along the network.

"Its spread is closely-linked with road salting in the UK.

"With the increase in concern for 'Health and Safety' we see gritters out on more occasions each year, especially in London, whether it snows or not.

"And it is a wind-dispersed species - cars whizzing past at 70mph are perfectly suited to whipping the seeds along the road.

"If you look at a distribution map of Danish scurvy grass you will see streaks of it heading inland which closely corresponds to the trunk road network.

"In future we will see it turning off onto the side roads.

"It is a very hardy species and survives well in the hot, dry, salty edges of the motorway.

"It flowers early, around this time of year, and this gives it a foothold through the hotter summer months - native species can't compete.

"As the temperature increases due to global warming we will see other native species dying out as they are not well adapted to extremes of temperature.

"In fact, motorway verges are some of the last wildflower refuges in this country.

"Over ninety per cent of our original lowland meadows have been nuked out of existence by ploughing and nitrogen fertilisation."