Above all there is an overwhelming sense of tranquillity punctuated only by the sounds of birds, bees and the sight of the odd rabbit hopping around.

The Derbyshire rabbits aren't too popular with Weleda's head gardener, Michael Bate, because they dig up whole plants to get their food. But rabbits aren't the biggest threat to the planet's herbs — we are.

A report last year by Plantlife International, the wild plant conservation charity, claimed that the £11 billion global herbal medicine industry is causing 4,000 to 10,000 herbs worldwide to become endangered. Unfortunately, the majority of the herbal medicine industry are not doing their bit to ensure survival and Weleda is one of just a few natural-health products companies growing its own and buying from sustainable sources.

An astonishing 80 per cent of the world's population relies on herbal medicine as their primary healthcare. Often the cost of drugs is far beyond the reach of many in the Third World but also, in many cases, local cultures have a long tradition of using herbal medicines that have served them well over the years.

In the UK we spent £87 million on herbal remedies in 2004, according to the market research group Mintel, which was an increase of more than 56 per cent on 1999 — with no let-up in annual growth. And all kinds of herbs traditionally used by medicine men, native tribes and Indian and Chinese doctors are now commonly available on the shelves of our local health-food store.

While many of us may applaud ourselves for embracing a natural lifestyle, the Plant- life report also claims that two thirds of the 50,000 medicinal plants used in the herbal industry are harvested from the wild, and herbalists talk of varieties that are no longer available at all.

It is almost impossible to police the harvesting of herbs around the world unless communities choose to do it themselves or herbal companies set up sustainability projects.

The Sioux Indians of South Dakota have used echinacea for hundreds of years to fight infection and to heal wounds and snake bites. When they collect the plants, to prevent the extinction of the species, they never pick the first one they see in case it is the only one of its kind left. Unfortunately, not everyone has such high ideals and echinacea is being illegally harvested even in protected areas in the United States.

Duncan Ross of Poyntzfield Nurseries, on the Black Isle, north of Inverness, is a biodynamic horticulturist who grows several endangered species there. “Anyone with a sense of sustainability will pick only a small proportion of the seeds they find with the landowner's permission,” he says. “But people who are simply in it for a quick buck do a lot of damage.”

Endangered herbs cited in the Plantlife report include arnica, popularly used in homoeopathic remedies for bruising; goldenseal, prescribed for digestive problems and wound healing; American ginseng, traditionally an aphrodisiac but now more usually dispensed to boost energy levels; and liquorice, often used in herbal and conventional medicines for stomach ulcers. The commonly known kitchen herbs, oregano and thyme, are also being overharvested in some areas for their medicinal properties.

It is often the type of harvesting that can cause problems. In the case of bearberry, or Uva ursi, a herb used to treat bladder conditions, only the leaves are required but the whole plant is uprooted for expedience. This happens commonly and as Ross explains: “If you pick the whole plant it doesn't seed again or regenerate.”

Most herbs grow easily in different climates and echinacea thrives even in the UK, but some of the most endangered species require considerable expertise, perfect soil conditions and the right climate. And many of them take several years of nurturing before they are ready to harvest.

Poyntzfield grows arnica on the highest point of the Black Isle to supply Weleda and medical herbalists. “It needs time and patience, and requires a sunny site with well drained soil, but because it is an alpine plant the snow and frost suit it well,” says Ross. “Goldenseal is harvested illegally in the Appalachian mountains for its golden root. We grow it here but it takes seven years to yield a crop.”

The report by Plantlife was critical of UK herbal manufacturers because most of them buy from unsustainable sources. It also claims that whenever there is a shortage of a particular herb, some companies buy plants on the open market that have invariably been picked in the wild without concern for sustainability, often because poor communities depend on selling them for their livelihood.

The kind of project environmentalists are keen to see is that adopted by the Swiss herbal manufacturer Bioforce, which grows most of its own herbs in Switzerland and claims to simply run out of stocks rather than buy on the open market.

Jen Tan, Bioforce UK's medical director, says: “Because the local tribes are poor and exploited by merchants, they try to get as much as possible from the plants which are hard to dig out of the desert. Devil's claw takes four years or more to mature, so it is extremely difficult for local growers to cultivate it without some injection of outside investment.

“After several years of research and the cultivation of devil's claw on an experimental farm in the desert, we have set up a local farmer with land, finance and housing to grow it for us on a sustainable farm on the South African border with Namibia,” says Ten.

The National Institute of Medical Herbalists is already drawing up guidelines for its 700 members advising that they use only herbs from sustainable sources. The institute also favours wildcrafting — picking from the wild only where it is known that herbs are not endangered.

There are encouraging signs that the industry is getting its act together slowly and in the past few years the UK company Viridian has launched its own range of 20 organic herbal tinctures, home-grown in Herefordshire, including echinacea, ginkgo and motherwort. Cheryl Thallon, of Viridian, says: “We always want to check the full provenance of the herbs we stock and, ideally, to watch the seeds growing in the ground.”

To become a member of Plantlife International call 01722 342730, or visit www.plantlife.org.uk

You can visit Poyntzfield Nurseries on the Black Isle: one-hour tours run once a month in June, July, August, call 01381 610352, or visit www.poyntzfieldherbs.co.uk Herbal rules The EU Traditional Herbal Medicinal Products Directive will come into effect on October 31. To register their products, manufacturers have until 2011 to produce a dossier that proves the efficacy of the remedies or they will no longer be able to sell them in the EU. This is good news for consumers. Some herbal remedies can be dangerous if taken in unregulated quantities or with other medication. But it may not be such good news for small companies. “It is very expensive to produce these dossiers,” says David Belshaw of Bioforce UK. “Larger companies like us are all right, but for some smaller companies the future is bleak.” Top selling herbs St John's wort — for skin wounds and depression. Echinacea — for infections, colds, flu and snake bites. Gingko biloba — for circulation and memory. Ginger root — for travel sickness and nausea. Black cohosh — for menopausal symptoms. Ginseng — for energy and as a libido booster.