Flower that became a national symbol-and a purple pain

It was only when huge areas of Iceland started turning purple that authorities realised they had made a mistake.

- Patrick Greenfield

By then, it was too late. The Nootka lupin, native to Alaska, had coated the sides of fjords, sent tendrils across mountain tops and covered lava fields, grasslands and protected areas.

Since it arrived in the 1940s, it has become an accidental national symbol. Hordes of tourists and local people pose for photos in the ever-expanding fields in June and July, entranced by the delicate cones of flowers that cover the north Atlantic island.

"The tourists love it. They change the dates of when they come to time it for the lupins. The flowers have become a part of Iceland's image, especially in the summer," said Leszek Nowakowski, a photographer based near Reykjavík.

"When people go to a waterfall or a glacier, they want to be stood around the flowers in photos," he added. "It makes it look epic... I had one guy who wanted me to photograph him proposing in the lupin fields with the waterfall in the background." But despite the scramble for photos each summer, Icelanders have become divided about the flowers - and scientists are increasingly concerned that they pose a threat.