‘Sudden oak death’ strikes at iconic Highland gardens

A tree disease known as ‘sudden oak death’ has struck at one of the world’s most renowned gardens in the Highlands.

Inverewe Gardens, near Poolewe in Wester Ross, has been affected by the nationwide spread of the tree disease Phytophthora ramorum.

The owner of the garden, conservation charity the National Trust for Scotland, has announced that it is removing affected larch trees, and other susceptible host plants, to contain the disease and prevent further spreading.

This work is focused on an area located in the garden’s east shelterbelt and associated areas of the main garden.

Phytophthora ramorum, a pathogen better known as ‘sudden oak death’ or ‘Ramorum dieback’, can also infest other types of trees, but is often referred to in Britain as ‘Larch tree disease’ because larch trees are particularly susceptible, and large numbers have been affected elsewhere.

Staff at the garden, which was created from a barren landscape by Osgood Mackenzie beginning the 1860s, were made aware of the pathogen before Christmas.

The Forestry Commission Scotland (FCS) notified the garden and issued two Statutory Plan Health Notices for the felling of the affected trees.

Inverewe, which is surrounded by a 2000-acre estate, has one of the most spectacular settings of any garden in Europe.

Warmed by the waters of the Gulf Stream, the garden supports a range of sub-tropical plants despite being perched on a northerly peninsula at the edge of Loch Ewe.

Keven Frediani, the NTS property manager for Inverewe, Kevin Frediani said: “Phytophthora is a fungus-like pathogen which can badly damage and often kill trees.

Since being found in the UK for the first time in 2009 it has spread rapidly and made it to the west of Scotland in 2011.

“Responsible landowners, like the National Trust for Scotland, undertake regular visuals checks from the ground.

“However, it was through the work of Forestry Commission Scotland, who undertake regular aerial surveys to support our checks for outbreaks of the pathogen, which identified the outbreak which can be spread by airborne spores from place to place.

He added: ““Fortunately, the affected larch are not in a core part of the garden, though the shelterbelt will have to be re-planted with a less susceptible species in order to ensure the garden continues to be protected from harsh winds in future, which is essential for the microclimate that garden enjoys.

“We are required to fell the affected trees up to 250 metres out as part of a containment zone, as well as removing Rhododendron ponticum in the vicinity that can also be infected.

“We will be able to do this using in-house teams by the February deadline, though the costs incurred to our charity will exceed £20,000.

“Our teams are working hard to ensure there will be very little impact on visitors or the overall integrity of Inverewe Garden, though we will be asking everyone to respect guidance which is designed to prevent any further infections or transference elsewhere.”

The actual source of the infection is unknown and given the propensity of spores to be blown over very long distances it is unlikely it will ever be identified.

Felling will be completed at Inverewe by the end of February and the wood will be disposed of using approved methods. Monitoring will continue thereafter to enable prompt action should a further outbreak be detected.