Jane Hepburn maintains three national collections

The recent opening of the Acropolis Museum in Athens inevitably reignited the debate about whether the Elgin marbles should be returned to Greece. But what about those other examples of British “piracy” (or conservation, depending on your point of view) – garden plants?

The UK has such renowned green spaces partly because of its forgiving climate – which nurtures everything from Arctic alpines to subtropical palms – and partly because of its imperial past, when merchants, explorers and later plant hunters introduced exotics from all over the world.

Over the years these plants were transformed into bigger, brighter, odder, more colourful species by enthusiastic breeders, amateur and professional. Nurseries stocked a cornucopia of choice specimens. Hilliers, one of the most renowned, once held about 8,000 different plants but by 1978, after two world wars and the advent of garden centres, the company had only about 3,500. This sad decline persuaded the Royal Horticultural Society to call a conference that in turn inspired the foundation of a charity called the National Council for the Conservation of Plants and Gardens, or Plant Heritage as it now prefers to be known. Until it arrived, cultivated garden plants, as opposed to species collected and protected by botanic gardens, faced extinction as soon as they fell from fashion.

Today the agency has encouraged amateur gardeners throughout the UK to create national collections. Typical of them is Mike Bell, a retired mechanical engineer who nurtures one of the country’s largest collections of bamboo at his Victorian terraced house in Wadebridge, Cornwall, south-west England. Here his favourite species adorn the front garden while rarities and hospital cases crowd in at the back.

Bell was ahead of the game. As he travelled round Britain for his job in the 1960s he became fascinated by the bamboos in old Victorian gardens. He began to collect species from cuttings.

“I found bamboos that would grow from nothing to 120ft in two months. It is the fastest-growing plant apart from seaweed but no one seemed to know anything about it,” says Bell, whose national collection of temperate phyllostachys – or bamboo – includes more than 600 forms.

Twice a week he takes his pickaxe, hammer, chisel and mattock (crucial tools to keep these astonishingly tough plants in order) and walks 15 minutes up the road to a one-and-a-half acre field where he keeps the rest of his collection.

“I must put across how invasive they are. There are two groups. One group are the clumpers, which come from mountainous regions and never run. The [second, the] runners usually come from lowland temperate regions and they are too invasive for most gardens. There are no in-betweens.”

Bell reckons that his passion costs about £1,000 a year, which, as he points out, is a lot less than most golf club memberships. So what are his favourites? In the same way that a parent will deny preference he demurs but, when pushed, names Chusquea Culeou because of its foxtail leaves and a form of Fargesia Nitida with deeper red-black stems than usual.

Parental responsibilities, or lack of them, plus a passion for roses, persuaded Jane Hepburn to become a national collection holder three times over – for Rosa spinosissima, or Scots roses; rugosa roses; and climbing and rambling roses.

“My children had grown up and departed, my husband disappears all over the world on business and I didn’t want to sit here twiddling my thumbs,” says Hepburn, whose 600-strong collections began life in 2003 in her five-acre garden in Ayreshire, Scotland.

The Scots roses and rugosas, with their delicate flowers in pinks, whites and reds, are planted in groups around the garden while her climbers and ramblers scale everything in sight, from the house to a purpose-built cloister walk, to various trees and boundary fences. Some are underplanted with delphiniums and alliums.

Hepburn began her collection with the help of the great rosarian Peter Beales, who supplied about 75 per cent of the initial stock. Then she had to start tracking down some of the more unusual specimens, such as heavily scented, deep red Rosa rugosa rugspin.

“Running a national collection isn’t difficult but you have to be dedicated. You have to keep records and you have to try to bring back rarer plants,” says Hepburn, who employs help once a week and claims that, apart from seasonal tasks such as pruning, feeding and spraying, the collection looks after itself.

This is nonsense, of course. Odd moments spent dead-heading or weeding with a mug of tea or a glass of wine in hand build up into days and weeks. For collection holders there is the added pressure of keeping three of each plant, along with meticulous records and reasonable public access on request.

Retired schoolmaster Gerald Goddard now has someone to help him run his national collection of the daisy-like tanacetum coccineum. He has held it since 1986, when he took nine cultivars to an RHS show in London and attracted admiration from the society’s hardy plants committee.

“I was asked if I would form a national collection. Back then you didn’t have to jump through hoops to hold one,” says Goddard, who nurtures 27 different tanacetum in his 100ft garden in Chingford, Essex, eastern England.

Through his work Goddard can claim to have saved Lady Randolph Churchill ... a white tanacetum named after the society beauty who gave birth to Winston Churchill. The flower is pretty but not nearly as exciting as the woman rumoured to have invented the Manhattan cocktail, sported a snake tattoo and charted a ship to care for wounded soldiers during the Boer war.