From the gardens of Buckingham Palace to an allotment in Sheffield, gardens hosting National Plant Collections come in all shapes and sizes. Such collections are often the work of individual enthusiasts, which raises issues such as continuity and cohesiveness.
Plant collections are listed and assessed by Plant Heritage. According to the organisation's plant conservation officer and acting executive officer Mercy Morris: "Many times collections are started by head gardeners who may move on, leaving the collection behind, or by committed individuals who become unable to maintain the collection as they get older."
Plant Heritage is addressing this by encouraging applicants to consider the long-term future of their collection when they apply for collection status, she says. "It can be a case of starting a charitable trust or arranging for it to be passed to a specialist society, but the key thing would be to make arrangements before it is too late."
Plant Heritage's North East group vice chairman David Goodchild holds the national collection for herbaceous Potentilla, of which he has 150 taxa in his garden. "Originally, my wife and I were looking for a group of plants that we both liked and were interested in researching," he says.
"One of the most difficult issues is what would happen to it if we weren't around - we haven't really talked about it. But there is a network of area groups that can help find a home for collections."
The number of national collections is more or less static at around 650. While this sounds a considerable number, there are many gaps, Morris admits. "We have a large list of missing genera, so there are many opportunities for those who are interested in starting a collection, and we also encourage duplicate collections."
Currently the Plant Heritage website lists more than 1,000 such "missing" genera, from the familiar Abies, the firs, through to Ziziphus, the subtropical jujubes.
The advantages to being a recognised collection holder include insurance for open days, a signboard, listing in The National Plant Collections Directory and website, a dedicated newsletter, free training sessions, research facilities and advice.
"They can participate in activities such as our marquee at Hampton Court Palace Flower Show and other shows," says Morris. Local area collections coordinator and area group are also on hand to assist, and there are collection holder bursaries available.
The National Trust for Scotland (NTS), Britain's second-largest garden owner, has 16 listings in the directory, including four at its famous Inverewe Garden in the northwest Highlands, as well as the Bergenia collection, numbering more than 100, in the more homely surroundings of Greenbank Garden south of Glasgow.
Not all collections consist of entire genera - others may be defined horticultural groups within them. The NTS also holds five Malmaison carnations at Crathes Castle near Aberdeen, for example, making it jointly the national collection holder with a private gardener in Ipswich. According to former NTS plant collections adviser Benedict Lyte, the distinctively clove-scented blooms "were immensely popular in the 1930s, but are difficult to grow".
But perhaps most distinctive of all, and the only collection unique to the trust, are the "Brodie daffodils" held at Brodie Castle in Moray. "We have identified 100 - it takes a keen eye," says Lyte, adding that some have even been re-imported from as far away as New Zealand. "We sell them from the garden in summer and ask customers to provide their names and addresses in case they are wiped out and need to be restored."
Such historical collections of bred varieties are particularly hard to complete, for obvious reasons. For example, Lyte says of the 19th century shrub roses at Malleny Garden south of Edinburgh: "We will never get the entire collection."
The trust also holds six national collections of Rhododendron, numbering more than 1,100 taxa in all. "They are the plants that the NTS, and Scotland's gardens in general, are best known for," says Lyte.
However, others have less obvious visitor appeal. Lyte says of the Tropaeolum (nasturtium) collection at Inveresk: "It's a tricky one to show because the tender ones are only in flower in early spring when nothing else is - the rest of the time it's just a row of pots."
National collections can enhance the research as well as heritage value of a garden. Liverpool University lecturer Dr Hugh McAllister was formerly deputy director of Ness Botanic Gardens, the national collection holder of Sorbus. "Many of the specimens are very attractive and many are also very rare and attract specialist visitors such as the RHS Woody Plants Committee, the International Dendrological Society and interested individuals, horticultural and scientific," he says. "The collection does give the garden national and international status, but the costs include the maintenance of good records."
Glasgow Botanic Gardens holds three national collections including a 350-strong collection of Begonia, supported by the ML MacIntyre Begonia Trust, and the basis for an ongoing research project on the genus at RBG Edinburgh.
Garden director Ewen Donaldson says: "Everything has to be kept correctly labelled because most are on display in our glasshouses. It enhances the status of our collection, which is useful to demonstrate to our funders, the city council."
The garden also holds the collection of Dicksoniaceae, the tree ferns, numbering around 30 - most of which were successfully rehoused in the rebuilt Kibble Palace within the gardens four years ago. Donaldson adds: "We are still adding to that collection, but it's hard to find room for them."
According to Plant Heritage, prospective Plant Collection holders should:
- Have three-quarters of the plants within the genus or other chosen scope and at least three specimens each of perennial plants.
- Be a member of Plant Heritage.
- Have an accessions policy in place.
- Be prepared to co-operate with holders of other collections, including selling or swapping plants.
- Have a robust back-up system in case plant labels or any other records are lost.
- Have a succession plan in the event of the death or disability of the collection holder.
HOW TO BE A RECORD HOLDER
A good many national collection holders are individual enthusiasts who get by with a stock of plant labels and a log book. But for larger organisations, holding collections of thousands of plants, a more systematic approach is required - both for ease of maintenance and to make the collections more accessible to the public.
According to Dominic Lyte of the National Trust for Scotland (NTS): "Knowing what you have informs future developments. You also avoid repetition across gardens - you don't end up with the same 'NTS flora' everywhere. We want each garden to be as unique as possible. And there have been numerous house fires in NTS properties down the years."
The NTS has employed the Demeter plant database, which was developed by the National Council for the Conservation of Plants and Gardens along with the NTS, the National Trust, the RHS and English Heritage, having been funded by the National Lottery and private subscriptions.
"Having a trust-wide database means each collection can be reported in a uniform manner," says Lyte. "We're not scientists or botanists but would like to be known as a reference point. We want people to trust our skills. There are about 70,000 accessions to NTS gardens that we know of and that could go up to 100,000. For each garden it lets the head gardener know which plants to concentrate on, where they come from and what parts of the collection to develop."
But he admits: "It's a bit clunky and we don't use it to its full capacity. But we would like to see it made available to the general public over the internet."
Demeter is based on the RHS Plant Finder database of more than 70,000 species and varieties. It has more than 100 users, most of whom are national collection holders, ranging from the NTS to Leeds City Council.
David Goodchild of Plant Heritage oversees development, installation and support for the package. "It can be used as a stand-alone system or across the intranet of a large organisation. I'm testing a new version now that will be compatible with Windows 7 - it will go into Beta testing in the next couple of months.
"It's designed to be future-proof - you can capture GPS data and integrate it with mapping software. We have looked at making the data available over the web. There's no reason why not, but that would take a fair bit of development."