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16 Jun 2023

The PLANTS project: initial findings

Written by Dr Colin McDowall, PLANTS Project Manager
A composite image showing some images of gardens and plants. On the top row, from left to right, are photos of two women by a banner advertising the PLANTS project; a close-up of a daffodil; and a woman kneeling by a flower bed taking notes. On the middle row, from left to right, are an extract from a handwritten plant list; some instruction manuals; and an open waterproof folder containing documents, lying on the lawn. On the bottom row, from left to right, are a close-up of a pile of silver plant tags; a close-up of a pale pink rhododendron flower; and a close-up of a yellow-flowering shrub.
Some highlights from the first year of the PLANTS project
The PLANTS project began in June 2022, with the aim of producing an inventory documenting the extensive collection of plants held across the Trust’s 39 gardens. One year on, some initial findings can be shared.

Since November 2022, the PLANTS team have been processing the large amount of data from the summer of 2022, and this has been supplemented by the data from revisits in spring this year. We have inventoried around 25,000 plantings [1] from 9 gardens [2] across Scotland so far, which translates into more than 9,000 taxa. The data has highlighted the scale, breadth and uniqueness of the Trust’s plant collections. For the first time, we have been able to get an accurate picture of the plants in our collection through up-to-date plant records.

We have come across a lot of interesting plants which are either original cultivars to a Trust garden, are rare species, unusual cultivars, or plants that provide a living link to the former owner of the garden. The PLANTS project has really inspired me to take a particular interest in the history of the plants we grow in our gardens today. A highlight of my recent holiday to Germany was visiting the Karl-Foerster-Garten nursery and garden in Potsdam, near Berlin. The nursery was founded in 1912 and led the way in breeding 370 plants; around a third of these specimens remain market leaders to this day. As just one example, the cultivar Rudbeckia fulgida var. sullivantii ‘Goldsturm’ was audited by the PLANTS teams at Crathes, Culzean and Threave.

As I pushed our buggy with my sleeping daughter through the garden, I reflected on how many cultivars have become garden staples, not only in my garden but around the world, and the PLANTS project continually came to mind. I realised that the collection of plants I was viewing told the story of the nursery and that, in their day, these plants were rare. A year into the PLANTS project, similar conclusions can be drawn from our surveys. In this story, I want to touch on some of the outcomes of our investigations so far.

For some properties, like Holmwood in Glasgow, we had very few existing plant records before the inventory. We have now recorded that two giant redwoods (Sequoiadendron giganteum) reside in the parkland as well as a Himalayan deodar cedar (Cedrus deodara). At Haddo House, we reconfirmed the status of conifers given to the house through the Royal Botanic Garden Edinburgh’s International Conifer Conservation Programme. The team also audited a truly remarkable grove of North American species such as the subalpine fir (Abies lasiocarpa) and mountain hemlock (Tsuga mertensiana), which nod to the 7th Earl of Aberdeen’s time as Governor General of Canada.

A view looking up the very tall trunk of a giant redwood tree from the ground.
A giant redwood at Holmwood

When I began in the role last year, I wasn’t expecting to discover plants that had been actually bred by National Trust for Scotland gardeners. However, since Threave became a Trust garden 60 years ago, its gardeners have been responsible for breeding many new cultivars. We have records of around 20 cultivars named after or linked to Threave, and the team found the following during their audits:

  • Abies koreana ‘Threave’ (Korean fir)
  • Colchicum ‘Glory of Threave’ (Autumn crocus)
  • Picea sitchensis ‘Kelton Hill’ (Sitka spruce)
  • Ozothamnus ‘Threave seedling’ (Kerosene bush)
  • Rosa ‘Threave’ (Rose)

These plants are rare and, in many cases, Threave has the only known example of the plant. All are believed to have originated from Threave and tell the story of Threave as a gardening school. Abies koreana ‘Threave’ and Ozothamnus ‘Threave seedling’ were selected by Magnus Ramsay, the former head gardener and instructor of Threave in the mid-1980s. Picea sitchensis ‘Kelton Hill’ was grown by another head gardener, Bob Brown, from cuttings taken from the wood on Kelton Hill (east of Threave House). The three specimens of Picea ‘Kelton Hill’ registered by the team in the garden may be the only three in existence.

This discovery of special cultivars was repeated at other gardens too. At Culzean, the team recorded the lovely forms of Crocosmia pottsii ‘Culzean Pink’ and ‘Culzean Peach’ that were bred on the estate. Another original plant (thought lost but has been rediscovered) is Primula ‘Inverewe’, which originated from the west coast garden near Poolewe. A hybrid between two of candelabra primulas – P. pulverulenta and P. cockburniana – it does not set seed and can only be propagated by division of plants. Therefore, it remains uncommon and is on the garden’s list for propagation.

One conclusion that can certainly be drawn from the first year of the PLANTS project is that the Threave-named cultivars should be preserved through propagation. Although it may be challenging, the Trust can now plan to reintroduce the missing cultivars to the garden.

A close-up of a deep orange primula flower, with clusters of delicate flowers growing around the main stalk.
Primula ‘Inverewe’

Another outcome of the first year of PLANTS is the discovery that many plants in Trust gardens provide a living link to the past. The previous owner of Crathes Castle, Sir James Burnett, was fascinated by viburnums, and the North team came across his collection from 1937. The oldest original plant at Greenbank Garden – a ‘Newton Wonder’ apple tree – tells the story of when the property was a kitchen garden.

However, one of the best examples of the link between a former owner and the plants in the garden is at Broughton House. Here we discovered a garden treasure box, filled with an interesting collection of plants. This ½-acre Kirkcudbright garden was developed by the artist Edward Atkinson Hornel. Originally, the garden would have been half its current size, but Hornel bought the house next door in order to extend his plot. The team discovered that some of Hornel’s original planting has survived. Broughton House’s archive has a letter from Hornel where he complains to a friend how he missed the first time the wisteria (pictured below) flowered as he was overseas. Wisteria is native to Japan, and it was Japan that most influenced Hornel’s designs for his garden. Hornel had first-hand experience of Japan, having travelled there in 1893 and again later in 1920–21. The number of unusual and rare Japanese plants found in this small garden should therefore not have surprised us.

A close-up of the delicate clusters of pale purple flowers on a branch of wisteria.
Wisteria in Broughton House Garden

Hornel was not the only gardener to live at Broughton House. His sister Tizzy, with whom he shared a home, was a knowledgeable plantswoman who spent much of her time working in the borders and in the greenhouse. She kept up a lively correspondence with nurserymen and had several plants named after her. During the audit, the PLANTS team came across a hardy orchid (Dactylorhiza) named ‘Tizzy Hornell’. Evidence of Tizzy’s love of gardening comes from the account given by Jay Charters, a housemaid at Broughton House in the 1930s, who said of her employer: ‘She never bothered you, she was out in the garden every day, taking cuttings an’ that.’ Hornel and his sister were inspired by the Arts and Crafts movement, creating a Japanese-style garden with stepping stones across a pond, erecting a glasshouse of Hornel’s own design and planting decorative trees.

There is debate as to whether the Japanese cherry trees (Prunus serrulata) were planted by Hornel, but the PLANTS project team also found rare plants from the Far East such as Paeonia suffruticosa ‘Kamada-fuji’. I was amazed to learn that Hornel brought back plant catalogues from his travels, such as those of the Yokohama Nursery Company. He designed part of his garden to resemble a Japanese sanctuary, with many plants imported directly from Japan. The Japanese theme has been skilfully pursued into the present by previous head gardener Nick Hoskins and current incumbent Mike Jack. We learned that, thanks to a donation from the Friends of Broughton House group, Nick had sourced a Paeonia suffruticosa ‘Kamada-fuji’ to match one found in Hornel’s original Japanese nursery catalogue.

Many valued staples in our gardens such as Skimmia japonica and the elegant variegated dogwood (Cornus controversa ‘Variegata’) came from Japan. The wall-trained climbing hydrangea (Hydrangea anomala subsp. petiolaris) that covers the whole wall of the studio is also Japanese and an original planting. While Hornel’s original Magnolia × soulangeana looks splendid in its maturity, the PLANTS team recorded for prosperity the apple tree (Malus) ‘Annie Elizabeth’, which was lost last winter to a storm.

Many of these mature trees and shrubs are themselves objects worthy of historical record, so future generations can know what was planted in the garden. In total, the project team discovered 12 cultivars at Broughton that are either threatened, endangered or vulnerable in cultivation; in other words, plants that are not widely available to purchase in the UK.

The importance of the PLANTS project is evident in the fact that it has uncovered these rare cultivars within the Trust’s care. This last year has taught me that plants are a cornerstone of Trust places. Not only do plants provide living links to the past, they also possess great ecological and scientific value. I look forward to more discoveries in the year ahead!

[1] A planting is a group of plants of the same variety.

[2] Threave, Broughton House, Culzean, Greenbank, Holmwood, Haddo House, Crathes Castle and Drum Castle

Plant Listing at the National Trust for Scotland (PLANTS) is the biggest horticultural audit project undertaken by the Trust and aims to celebrate, protect and better understand the flora and vegetation across our gardens and designed landscapes.

Read more about the PLANTS project

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