Gardens: Only collect

For some gardeners, it's just a case of having a favourite type of plant they choose to grow in abundance. For others, this interest develops further and before they know it, their lovingly tended selection of favourite plants ends up as a National Collection. There are around 650 National Collections in the UK, in private and public gardens, and a good number of these are in Scotland.

"Our collections holders are as diverse as the collections themselves and range from royalty to allotment holders and back garden enthusiasts," says Nicola Savage of Plant Heritage, the charity which looks after the National Collections. "HRH the Prince of Wales has two collections at Highgrove (Fagus and Hosta]; we have local authorities, zoos, botanical gardens, stately homes and colleges with Collections. Some of the holders are professional nurserymen or nurseries and many are amateurs who have dedicated years to developing their collection and are often international authorities in their field."

The National Plant Collections Scheme grew out of a Royal Horticultural Society conference,"The practical role of gardens in the conservation of rare and threatened plants". The event highlighted how the variety of cultivated plants available to gardeners was shrinking, largely due to financial factors - nurseries were cutting back on the breadth of stock offered in their catalogues; local and central government and education establishments were operating within tighter financial constraints and the price of labour was making private gardens harder to maintain.

"Many of the plants in our collections have great pharmaceutical, cultural or historic value or other qualities - such as drought or pest resistance - that make them worthy of preserving," says Savage. As well as administering the National Collections, Plant Heritage co-ordinates local groups throughout Scotland and the UK, offering members the chance to take part in events such as rare and unusual plant sales, lectures and visits to interesting gardens. The charity aims to encourage the propagation, conservation and research of cultivated plants in Britain, at the same time educating the public about the importance of cultivated plant conservation.

Graham Duncan is First Gardener at the National Trust for Scotland's Greenbank Garden in Glasgow, home to the National Collection of Bergenias. "At present we have 113 varieties, with most planted together in one plot of the garden," he says. "When the Bergenia are in full flower they always cause comments from visitors, with most varieties flowering at the same time, usually from the beginning of May for three to four weeks." Several other National Trust for Scotland properties hold National Collections, including Crathes Castle, Brodick Castle and Malleny House - full details of these and other properties with National Collections can be found at www.nts.org.uk

Nicola Savage explains that National Collections must contain 75 per cent of the plants available for the "scope" of the collection. So, for example, if the collection's scope is defined as the genus Dianthus, a popular plant with quite a large number of varieties, the collection could number over 95 types, whereas if the scope is defined more narrowly - ie a collection of a particular sub-set of the genus - such as the Malmaison type of Dianthus, the collection might contain only five plant types. Other requirements are that the collection must have three of each plant; they should have been in situ for at least a year and plants must be labelled and records kept. At the Royal Botanic Garden Edinburgh (www.rbge.ac.uk), a large portion of several National Collections of international importance are on display in the Montane and Wet Tropics glasshouses. "The first Aeschynanthus came to the glasshouses in 1955 and the collection has gradually built up over the years with plant collecting expeditions to South East Asia," says Louise Galloway, Supervisor of the Indoor Department at RBGE. "This ties in with the history of our Vireya Rhododendron collection (another National Collection and the largest cultivated collection in the world) as these plants can often be found growing together in the rainforest of South East Asia." The garden started growing Vireyas in the early 1950s, with just a handful of plants and now has over 180 species. The other National Collections are all types of ginger, which, again, have been built up since the 1950s.

The Aeschynanthus are stunning plants to look at - they are epiphytes which grow on branches of rainforest trees and have mostly red and orange flowers. "Many visitors recognise the Aeschynanthus as some species are cultivated for houseplants and the common name is lipstick vine because as the flower starts to come out, it looks like a lipstick," says Galloway. The Vireya rhododendrons are tropical so don't flower only in the spring like the hardy species - they also flower right through the winter months, and the gingers are equally appealing to children and adults alike with their large, waxy flowers. "We like growing these plants as they are unusual, often with very attractive foliage and flowers, they're not widely cultivated and often prove a challenge to grow," says Galloway.

Many National Collections, like the ones at the RBGE and National Trust properties, are in public places and can be easily viewed at any time of the year, while those in private gardens are usually open by appointment and on official Open Days. If you think your own garden collection is worthy of inclusion, contact Plant Heritage to find out more.

"We welcome new applicants," says Nicola Savage. "They don't need a huge garden or greenhouses to have a collection - there is sure to be a plant type out there to suit any enthusiast." So whether you are a grower or just an admirer of a particular type of plant, these specialist collections are a great way to find out more about your favourites.

For full details of all National Collections, visit the Plant Heritage website: www.nccpg.com

This article was first published in The Scotsman, Saturday August 14, 2010