The disease, commonly known as sudden oak death, was first found at the garden in 2007 and has affected several forests across Scotland.
National Trust for Scotland (NTS) has been managing the outbreak but has now put in place a full-scale operation at Arduaine Garden as part of a four-year plan to protect the garden, while boosting its biodiversity and resilience. The project starts this week and will cost £250,000 in total.
Trust arborists and horticultural experts will uproot, process, and then mill the affected trees on site. This will kill disease in the wood, allowing it to be recycled and transported for other purposes without fear of spreading infection.
Among a variety of uses for the felled wood will be the creation of an organic, Queensferry Crossing-inspired windbreak to replace the larch shelterbelt, which enables the garden to grow species from as far away as East Asia and South America, including a renowned selection of rhododendrons.
In the area where the larch will be removed, the National Trust for Scotland intends to plant a variety of new tree species which are more resilient to disease, including black pine, birch, western red cedar, goat willow, and sycamore. The conservation charity expects the initiative to be completed by the end of March 2022.
NTS gardens and designed landscapes manager Simon Jones, said: "We’re doing what is scientifically and morally right for the state of plant health in Arduaine Garden and beyond. While we can’t be definitive about removing disease from the property altogether, this innovative approach will go some way towards helping us protect this historic garden from future outbreaks of sudden oak death, by creating a more diverse and resilient arboretum."
In 2007, several of the garden’s Japanese larch were diagnosed with the first cases of Phytophthora ramorum in Scotland and were earmarked for removal. The disease spread and, in 2016, a statutory notice for the trees’ removal was issued.
The £250,000 project at Arduaine Garden is part of the National Trust for Scotland’s programme to invest almost £60 million over the next five years. It is also an example of the ‘100 Ways’ the National Trust for Scotland is protecting Scotland’s heritage and is among the Trust’s priority projects for 2018-19.
Jones added: "These are the first steps in what will be a long and thorough process – it’s important that we get this right for the future of the garden. It’s another example of how we’re investing significantly in Scotland’s natural heritage, to maintain and enhance the way we celebrate its history and culture for current and future generations.
"We very much see the project at Arduaine Garden as an exemplar of what we do for the love of Scotland and what a designed landscape could look like in the future. It will also go some way towards forming how the National Trust for Scotland goes about conserving many other parts of our natural environment."