Beautiful, exotic and rampant – foreign invader's deadly threat

IT IS an attractive plant that produces pretty pink or purple flowers. However, its beautiful appearance should not disguise the threat it poses to one of Scotland's most popular birds.

Tree mallow, or Lavatera arborea, right, , is native to Mediterranean countries. It grows up to nine feet in height and can spread until it resembles a forest. Its root networks smother areas where puffins create their burrows, preventing the birds from returning to lay eggs and rear their chicks.

The plant, which has existed on islands in the Firth of Forth since the 17th century, thrives in exposed coastal locations.

It is believed lighthouse keepers brought it to Bass Rock in the Firth because of its variety of uses. When the leaves are steeped in hot water they can be used on sprains and burns. And the plant can be used as an animal food – it is thought the lighthouse keepers used it to feed their sheep.

For hundreds of years it grew without causing any harm on Bass Rock.

However, when temperatures began to warm up over the past few decades, it began to spread rampantly, and soon infested the nearby islands of Craigleith and Fidra, home to large colonies of puffins.