Mediterranean Garden Society

Kew Without a Roof a Brief History and Tour of Tresco Abbey Gardens

by Lucinda Willan
photographs by Lucinda Willan

Photographs to illustrate the article published in The Mediterranean Garden No. 112, April 2023

The photo at the top of this page shows a view from the top of the Neptune Steps looking along Lighthouse Walk to the sculpture of The Tresco Children at Tresco Abbey Gardens (Photo Lucinda Willan)

Situated 30 miles off the tip of Cornwall on a small island is a garden unlike any other, certainly in the UK and arguably in the world. Tresco Abbey Gardens has been developed and nurtured by the same family for nearly 200 years and houses a collection of over 20,000 species of Mediterranean and sub-tropical plants across its 17 acres. It is a marvellous survivor from the golden age of garden-making and plant collecting and is often called ‘Kew without a roof’ due to its botanical treasures and the fact that the oceanic climate on the island of Tresco, warmed by the Gulf Stream, allows all sorts of plants to be grown outside that would need glass protection on the British mainland.


Turquoise waters and white sand beaches

The story of the garden began in 1834 when Augustus Smith became the Lord Proprietor of the Isles of Scilly. He took out a 99-year lease from the Duchy of Cornwall and became responsible for all aspects of the running of the islands and the welfare of their inhabitants. Smith chose Tresco as the island on which to make his house and base. Nestled in the centre of the archipelago of the Isles of Scilly, in a relatively sheltered position, you can see why it was Smith’s chosen spot - with its turquoise waters and white sand beaches you would be forgiven for mistaking it for a Caribbean island. A Benedictine priory had stood on the island since 964 AD and had been developed from the 12th century by the monks of Tavistock. It had originally been known as St Nicholas’s island but by the early 14th century it is referred to as trescau meaning a farm of elder trees. St Nicholas’s priory suffered throughout the 15th century due to attacks from pirates and is thought to have finally been abandoned in the late 15th century as a result of these pressures rather than the Dissolution of the Monasteries in 1536-1541. When Smith arrived it was a picturesque ruin and, seeing as it was at the height of the Romantic Period and that the site had the benefit of fresh water, he decided to build his house and garden around it.


Gothic arches in the ruined priory

Smith recognised the potential that the frost-free environment had to develop a plantsman’s paradise but had to find a way to protect his garden and house from the ferocious salt-laden Atlantic southwesterly gales. His solution was to build a four-metre-high granite wall and develop shelter belts planted with Pinus radiata, Monterey Pine, and Hesperocyparis macrocarpa, Monterey Cypress – both fast-growing, salt-tolerant species native to California. The shelter provided by these giants enabled the garden to thrive and as they grew so did Smith’s plantsmanship and collection. In the 19th century exotic plants were one of the great luxury goods and status symbols of the age. Smith was a man of means and energy and he corresponded with the great gardeners of the period, including William Hooker at Kew, and through these friendships he was able to develop the plant collection rapidly and fruitfully.


The Mediterranean Garden

The garden has a scale and ambition that I find incredibly exciting. It rises gently across the southern half and then vertiginously in the northern half giving the whole space a swooping quality. It seems to soar and expand and contract as you move through the different areas. Smith laid out the main features of the garden as we see it today. He was responsible for the construction of the terraces and the establishment of the axial routes that divide up the garden – horizontally the Long Walk, Middle Terrace, Top Terrace and the vertical element of the Neptune Steps. Smith was also the one who started to create spaces for particular plant communities from different areas around the world. This interest in ecological planting has continued throughout the different generations of the family and makes the discovery of the various areas all the more interesting. The planting is clearly thematic but it is not slavish. Plants are placed where they are most likely to thrive. The exposed top part of the garden with its poor soil and high light levels is predominantly home to plants from South Africa, Australia and Mexico, the Middle Terraces are more sheltered and are planted with mainly Mediterranean, Canary Islands and South American flora and the Lower section is the most sheltered with richer soil, lower light and greater humidity and houses many subtropical woody plants mainly from New Zealand and Chile.

There is never a bad time to visit Tresco Abbey Gardens, although the weather can make it very difficult to get there by helicopter or the sickness-inducing flat-bottomed Scillonian ferry. The average year-round temperature is 15 degrees Celsius and the temperature rarely gets below 6 degrees or above 19 degrees. Annual rainfall is usually around 800mm and the average humidity is 80% due to the proximity to the sea. This microclimate and the number of Southern Hemisphere plants mean that even in the dead of winter the garden is full of flowers and since 1862 there has been a New Year flower count on 1st January which records this extraordinary phenomenon. The tally is usually around the 300 species mark. I decided to try the same thing at Sparoza this year and was delighted to log 117 species in flower.


Top terrace

Whenever I visit Tresco Abbey Gardens I always find myself rushing through the Mediterranean Garden up to the enormous Hesperocyparis macrocarpa that stands sentinel over this part of the garden and on through the succulents until I reach the Top Terrace. Oddly, it is from this point that I feel a tour of the garden begins, or should begin. This is the highest point in the garden and offers a spectacular panoramic view across the garden to the neighbouring islands of St Agnes and St Mary’s. The planting is buttressed to the north by the dense woodland shelter belt and to the south falls sharply away punctuated by the tall spires of the Canary Islands date palm, Phoenix canariensis, and the Norfolk Island Pine, Araucaria heterophylla, so that you almost feel as if you are in the overstorey. This view has a prehistoric quality to it and always makes me think of dinosaurs.


The huge 10 metre tall Quercia ilex hedges and clipped Coleonema album that line Lighthouse Walk

The planting of the Top Terrace is largely made up of rare plants from South Africa, Australia and Mexico but is not laid out in the schematic displays of many botanic gardens. Here, wide gravel paths edged with stands of Amaryllis belladonna are surrounded with dramatic plantings of Proteaceae and Cape heathers. Erica mammosa, E. coccinea, E. glandulosa, E baueri subsp. baueri, E cerinthoides and E diaphana are scattered throughout the area bringing a flamboyance and glamour that I have never associated with heathers before. These are juxtaposed with a huge and incredibly flamboyant Telopea speciosissima and a wide array of proteas in all different shapes and sizes, Protea eximia, Protea ‘Pink Ice’, Protea cynaroides, Protea grandiceps and Protea susannae to name but a few of the extraordinary different varieties. Interestingly, my last visit in September made me look at this area with fresh eyes.

It was the first time I had visited since working at Sparoza and I realised that some of the plants that in previous visits had felt completely alien were now like old friends. Mounds of Coleonema album, Coleonema pulchellum 'Sunset Gold' and Eriocephalus africanus are used throughout the planting and made me look at other plants with an appraising eye. Could Phylica ericoides or Acmadenia heterophylla work at Sparoza? Could they cope with our alkaline soil? As you move along the Top Terrace you encounter granite walls topped with a wig of bromeliads, Fascicularia bicolor and Ochagavia carnea, and an impressive show of acid-loving Australian trees. A stand of Banksia integrifolia creates an archway of foliage and flower and reaches out across the terraces framing the view with their bright yellow candles.


A view across the planting between the Top and Middle Terraces

To descend to the Middle Terrace you can either follow the narrow snaking paths that wind through the beds of aloes, aeoniums and agaves or you can take the grand granite staircase of the Neptune Steps from which you can see one of the most iconic views of the garden – a magnificent swooping avenue that falls and rises again like one of the vistas from the Villa d’Este. The steps are framed by Phoenix canariensis and planted with a cascade of aloes, agapanthus and dasylirion which look like exploding fireworks all the way down the hillside. The walls are topped with mellow terracotta pans overflowing with vibrant seasonal displays.


The Neptune Steps

The Middle Terrace is the heart of the garden and has a wonderful drama and yet in spite of the scale it feels sheltered and intimate. The upper section appears like a theatre of plants and the huge palms and pines frame the view. Across this central section off the main walkway the garden becomes a labyrinth of smaller spaces and garden rooms. I love the rock garden of cascading Puya chilensis, aloe species and aeoniums and the grotto/summer house on this level. It overlooks a small fish pond and is topped off with the family emblems of an elephant and gloved fist almost disguised by the swags of ipomoea, Passiflora antioquiensis and Tecoma capensis.


A view from inside summer house on the Middle Terrace

All of these different garden rooms have their own qualities and personality but the area around the ruins of St Nicholas’s priory is one of my favourites. The Gothic arches are studded with Aeonium cuneatum, Erigeron karvinskianus and even the odd self-seeded agapanthus. Even after the dissolution of the priory the ruined buildings retained a special significance for the people of the island and they continued to bury their dead in the abbey precincts so the exuberant planting surrounds the beautiful lichen-covered headstones of long-dead islanders.


Lichen-covered headstones

In the lower section of the garden towering Quercus ilex hedges create thick organic walls to create further windbreaks to protect the plant collection. It is in this section of the garden that the planting feels its most shaded and jungly. Enormous Metrosideros excelsa are dotted through this area, their aerial roots hanging down like banyan trees. One even straddles a path so that you pass through it. The green tunnel of the Long Walk has a feel of a cathedral of trees, all tropical textures in different shades of green occasionally made even more exotic by the appearance of a golden pheasant or two. These extraordinary birds roam free around the lower reaches of the garden and the lawned areas; their primeval calls reverberate around the garden increasing the sense that you might encounter a dinosaur. This section feels as if you have passed into a different world and I find I often look up to marvel at the lacy fronds of the tree ferns, the incredible bark of the impressive Luma apiculata, or the flowers of an exotic beauty such as Saurauia napaulensis or Lapageria rosea.


Tree ferns below the Long Walk.

Tresco Abbey Gardens is one of the great gardens of the world. It is a rare survivor from the 19th-century tradition of plant exploration and garden-making and this ethos of expanding and adding to the collection continues under the current custodian, Robert Dorrien-Smith, and his curator, Mike Nelhams. It has the plant collection of a botanic garden but the beauty and whimsy of a private garden. Whether you are a plant connoisseur or someone who loves visiting gardens, it has something for everyone and is well worth braving the Scillonian ferry for.


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