Gardening: Something noxious in the nursery: Even seemingly innocent plants can cause blisters and rashes, but which ones? Michael Leapman reports on a scheme to alert nervous buyers to baddies in the borders

As the hazards of everyday life become fewer the health and safety lobby grows more influential. No doubt there is a causal connection but the result is that the nannyish tendency, having won the big battles, spreads its tentacles into areas of more marginal concern.

The latest victims are garden centres and plant nurseries, which have been persuaded reluctantly to start labelling plants and bulbs with warnings of the harm they might do you. These labels will begin to appear at retail outlets next year.

In case you are tempted to think of your garden as one of the least menacing areas of your home, take a look at the code of practice for cautionary labelling just issued by the Horticultural Trades Association. Coming on it cold, you could be forgiven for concluding that mortal peril lies beneath every innocent leaf and on every shimmering petal. In fact, as Bob McKinley of the HTA is at pains to point out, that is not so.

''There aren't any plants on sale that are so toxic that you shouldn't really buy them,' he says, 'and we don't know of any that have caused death. We are talking here about a skin discomfort which will probably only be temporary, or a rash that just could leave a scar, or a stomach upset that could be more or less severe.'

Dr McKinley knows of no other country whose garden suppliers operate such a labelling code. So why has it been issued here now? A sudden outbreak of nasty spots among the green-fingered? A craze for lupin-eating at smart dinner parties? A spate of groaning customers clutching their tummies and fighting for the loos at garden centres? None of these, as it turns out: the closest we can get to a trend is a newspaper story not long ago of a publican rumoured to be serving daffodil sandwiches.

'We were under pressure,' Dr McKinley concedes, 'mainly from the Consumers' Association. And we feared that in today's climate someone might go to litigation if they were harmed by some plant they'd bought. The retailer does have some responsibility for informing the public of any risk.'

The pressure took a long time to produce results. Rose Ward, principal researcher for the CA's magazine Gardening Which?, says the association's campaign began in 1983, mainly as a result of concerns expressed by members of the public. Gardeners wrote in about mystery rashes and parents were worried that their young children might have put something poisonous in their mouths.

'Certainly they weren't falling over like flies,' she concedes, 'but there did seem, for instance, to be a big increase in skin blisters from rue.' This fashionable shrubby herb contains sap that, if you get traces of it on your skin and go into the sun, can cause painful sunburn and blistering.

At first, the CA met with stubborn resistance from the nursery trade. 'For seven or eight years they kept on saying: 'Go away; it isn't an issue; don't be silly',' Ms Wade reports. 'But then when we raised it again in 1990 they were more favourable, perhaps because they were worried about consumer protection legislation.' Although pleased with the code in principle, Ms Wade is disappointed that the trade is being allowed as long as three years to comply with it.

Dr McKinley admits that members of the HTA were divided on labelling plants: 'There was a lot of opposition,' he concedes. 'One extreme is that you shouldn't label anything because everybody knows that some plants can be harmful - and they'll get over the effects in a couple of days. These people thought they would lose sales because of the labels. The other extreme is that if there's potential for harm of any kind you shouldn't be selling the plant in the first place.'

The resultant code is a compromise between those two positions. The Consumers' Association would have liked the labels to carry the conventional warning sign - an exclamation mark inside a red triangle - but the trade thought that would be unnecessarily alarming.

For the same reason, the word 'poisonous' is carefully avoided - except for one exceptional case - because it is redolent of those Agatha Christie stories where a husband slips something nasty from the garden into his wife's cocoa and the maid finds her prone in the library next morning. (In practice your aspiring poisoner would be hard put to find any plant lethal enough to produce such a stark effect, unless it was administered in impossibly large doses.)

In the code, the word 'poisonous' is used only for poison ivy. This pest, more common in the United States than Britain, is the sole plant to qualify for Category A, under which 'the sales of these plants should be restricted and sales to the public discouraged'.

Poison ivy secretes an irritant that invariably causes severe blistering on contact with the skin and can make you ill - though not fatally - if you eat it. It is very seldom cultivated in gardens but it qualifies for inclusion because there are records of it being sold by one or two British nurseries. If it were a weed and not offered for sale it would not have made the list: giant Japanese hogweed, which produces a comparable though milder reaction, is excluded for that reason.

Category B contains 26 plants. These 'require a warning on the plant label and on any bed label or any other point-of-sale material'. The word 'caution' has to be included as part of the warning. The tables below are compiled from this list: among everyday plants surprisingly implicated are lilies and autumn crocus.

Plants in the final group, Category C, require a less stern warning and the word 'caution' need not be used. Where the Category B plants are described as 'toxic', here the effects are watered down to 'harmful if eaten'. Plants on this list (37 in all) include tulips, daffodils, lupins, chrysanthemums and common ivy.

The HTA has been working on the code for three years, in conjunction with scientists from the National Poisons Unit at Guy's Hospital and the Royal Botanic Garden at Kew. At all stages they had to consider whether an ill effect was common or exceptional. Some people can be allergic to almost anything, and no plant was included unless case histories showed the adverse reaction to be fairly widespread.

Nor does the code take into account the peculiar things people might do by way of experimentation. 'It's unbelievable what some people will do with a plant,' says Dr McKinley. 'They'll make tea out of it, or mash it up and bind it on their wounds, or put it in a pipe and smoke it. They take the risk on themselves. We're only looking at plants in an ordinary domestic situation.' He and Ms Ward agree that the labelling will be specially important for parents of young families. Some toddlers will put anything into their mouths.

'The garden should be a safe haven really,' Dr McKinley believes. 'If you've got children you feel might start gnawing at things then you can still buy these plants, but put them at the back of the border instead of the front - and teach your children not to eat strange plants.

'Something that's confused matters over the last few years is the tendency to grow ornamentals and edibles mixed in together. If little Willie sees carrots growing in the herbaceous border and Daddy starts nibbling them, how does he know that the flowers next to them aren't safe to eat?'

House plants are also vulnerable to infant experimentation because young children, especially babies, spend more time in the house than the garden. Dieffenbachia, or dumb cane, is among the guilty, being both toxic if eaten and a skin irritant if over-handled. And the merest whiff of Primula obconica - sometimes called the German or poisoned primula - can bring some people out in spots.

The last thing Dr McKinley and the HTA mean to inspire is panic. 'We don't want to alarm the public. We simply want to strike a balance between keeping people informed and

inflating the whole issue out of all proportion. After all, easily the most common accident in the garden is damage to your back.'

Heigh ho; something else to worry about.

The code of practice for labelling potentially harmful plants can be obtained for pounds 3.50 from the Horticultural Trades Association, 19 High Street, Theale, Reading, Berks (0734 303132).

BEWARE OF THE PLANT

CATEGORY B

Plants that are toxic if eaten and that irritate the skin:

Arum (lily); Daphne laureola; Daphne mezereum; dieffenbachia

Plants that are toxic if eaten:

Aconitum (monkshood); autumn crocus; deadly nightshade; daphne (all varieties); datura (angels' trumpets); foxglove; Gaultheria pernettya; Gloriosa superba (glory lily); henbane; laburnum; lantana; lily of the valley; Nerium oleander; phytolacca (pokeweed); Ricinus communis (castor oil plant); Solanum dulcamara; veratrum; yew.

Plants that irritate the skin:

Dictamnus albus (burning bush); Primula obconica; rue

(Photograph omitted)