Protecting and enhancing the diversity of the world in a unique and completely unexpected destination
Inverewe ©National Trust for Scotland
Situated in the extreme north-west of Scotland, just under the 58th Parallel, Inverewe is an arboricultural anomaly. Sited in an extreme landscape between the mountains of Wester Ross and the Atlantic Ocean, it is a garden on the edge. Full of wildlife that is rare elsewhere in mainland UK, it teems with botanical wonders collected and then nurtured in a man-made landscape fashioned over the last 150 years.
It is a garden that is afforded essential protection by a shelterbelt of native and nonnative trees that grow on modified soils which were formed by importing soil in the late 19th century as ballast to enrich the base of thin peat soil that lies over Torridonian sandstone, some of the oldest impermeable rock in the world. The plant collection thrives in the location which is blessed with the warming influence of the Gulf Stream and benefits from a south-facing slope; the site was chosen and then the shelterbelt planted to create a nurturing microclimate with conditions similar to those found much further south in Devon and Cornwall’s favoured coombe valleys.
The garden is the result of the vision and dogged determination of one man, Osgood Mackenzie, who waited 30 years before planting up natural windblown coupes and his own clearings with ‘exotic bundle plantings of shrubs and trees’ in his ‘experimental garden’, a practice that was successful and that resulted in a legacy known as the ‘impossible garden’ from his writings in the RHS Journal in 1914. Work on his legacy was continued by his daughter Mairi Sawyer’s artistic hands, and Inverewe became the ‘Oasis of the North’. Dreaming an impossible dream, by turning thin peat into fertile loam they ensured a barren landscape would grow one of the world’s top gardens, sheltered from the elements by a wall of trees.
In recent years, the trees and the shrubs that afford the garden protection have faced a number of challenges related to the growing impact of global change, with increased occurrences of extreme weather events, and emergent pest and disease incidents associated with climate change and the movement of plants and their vectors, including human-aided transport of problems between sites.
Innovation at Inverewe
In this context, recent work has been undertaken to review key challenges that the plant collection is facing in the early decades of the 21st century. Three focus areas have subsequently been highlighted as examples of emerging threats to Inverewe as a garden, arboretum and work of art. These include environmental challenges from increasingly volatile and unpredictable weather events (extreme wind, rain and unusually dry periods), emerging pests and diseases (novel and without approved or natural controls) and the age of the original collections (lack of propagation in the past and less availability in the trade or access to wild material under the Convention of Biodiversity).
To help address these challenges the garden has been exploring complementary husbandry practices that help optimise the vitality of the current collections through managing and building optimal soil health, including annually returning 100 tonnes of green waste as a soil amendment, improving soil hydrology through investing in drainage, and monitoring biological activity changes over time.
This edaphic environmental improvement is complemented by above-ground attention to the density of planting in the shelterbelt, managing its composition to diversify the structural age class and optimise condition based on informed surveys, including an i-Tree Eco study in 2017/18 which is now helping to optimise ecosystem benefits and inform the selection of species better suited for future climate modifications under IPCC (Intergovernmental Panel on Climate Change) predicted climate scenarios.
A £500,000 investment in a SMART greenhouse has enabled work to start on the propagation of the older specimens found in the Inverewe collection, identified through the historical register of plant records and currently maintained in the Demeter Plant Heritage Database. This work is being written up into a more detailed review with case studies that include the impact and management of a Phytophora outbreak in 2016, which saw 2,000 larch felled under a Statutory Plant Health Order; the ongoing management of camelia cottony scale, which has devastated some of the older collections of rhododendron that were growing at Inverewe; and the mitigation of the effects of episodic weather by building resilience into the collections and significantly the shelterbelt, including the creation of a new experimental garden on the edge planned for 2020/21. More information on this important project for Inverewe, which has wider benefits to help inform all heritage collections in the UK and beyond, can be found in the next issue of Sibbaldia (the Journal of Horticultural Science with free access from the RBGE website), due out before Christmas 2019. The article will present Inverewe as a landscape that endures through adaptation to social, economic and, increasingly, environmental challenges which shape the direction it takes as a garden and a plant collection growing on the edge.
A place like no other
As the outgoing Operations Manager and lead for the past four seasons at Inverewe, I can honestly say it is a garden like no other that far north. It is well worth a visit to be inspired by the apparently impossible task of establishing such a collection. From its growers’ walled garden to the surrounding plantsman’s paradise, it is unique in setting and quality, with its arboretum of diversity.
Under the National Trust for Scotland’s stewardship, Inverewe is internationally respected today for its plants, from domestic vegetables to 10ft tall Himalayan lilies and the Asian rhododendrons that sit in the dappled shade of the forest of pines and oaks. Such diversity and quality are not normally expected outwith the tender garden estates in the south-west of England, and certainly not in the Highlands of Scotland – an adventurous, dramatic landscape that is blessed with big skies and ever-changing seasonal beauty.
Since 2016 the garden has been augmented by an innovative museum, a cultural art gallery and Inverewe’s own farm. The community have embraced the diversity of events and cultural experiences the property brings through its planned events and activities, from forest bathing for wellbeing to open air theatre, from adventure travel and film to specialist garden festivals and immersive ranger-led experiences to see the biodiversity of Wester Ross – it really is ‘like no place else’.
This article was taken form Issue 187 Winter 2019 of the ARB Magazine, which is available to view free to members by simply logging in to the website and viewing your profile area.