Tree Mallow – To Grow or not to Grow?


So what might connect a Wenvoe garden with the small island of Craigleith in the Firth of Forth? The answer – Tree Mallow. Gardeners will be familiar with the various Mallows grown in gardens and sold by Garden Centres. Or you might have tasted Marshmallow flavoured originally with an extract from the root of the plant that grows on our coasts, particularly Gower. The Tree Mallow is quite unmistakeable growing typically to 2 metres and even reaching 3. If you are visiting Gower there are a few near the Youth Hostel at Port Eynon and these are around 3 metres. One turned up unannounced in our garden so out of curiosity we let it grow. It is currently 1.40 metres and still shooting up vigorously but not yet in flower. It is native to the Mediterranean and Atlantic coasts, in Britain mainly in the South and South West.

But why Craigleath? This small island near North Berwick and others close by are a haven for sea birds, especially puffins but in the early 2000s it was clear that the numbers were plummeting and the cause was – yes, you've guessed! – Tree Mallow. The plant can grow out of control forming a thick mini-jungle and preventing birds like puffins getting to their nesting sites. Few other plants can survive under the dense foliage. But the good news is that as volunteers have started clearing the Mallow the puffins are returning.

But how does a plant associated with the South West end up on remote islands in the North East? In this case it was introduced by soldiers serving on nearby Bass Rock because it was used to dress wounds. Also lighthouse-keepers elsewhere have planted it for similar reasons, to use in poultices and in ointments to treat burns. So there is your conundrum – if one turns up in your garden do you let it grow and risk it taking over and keeping out the puffins or remove it and lose a useful ingredient in nature's medicine chest?