If you missed World Naked Gardening Day, don't worry – you may have saved yourself a world of itchy skin conditions, writes FIONNUALA FALLON

IT WAS WORLD NAKED Gardening Day a few weeks ago – an event that might have entirely slipped my notice were it not for the valiant efforts of a few brave Irish gardeners to publicise it (you know who you are). My curiosity piqued, I then came across the WNGD website, which is illustrated with photographs of lots of naked people picking flowers, dancing together in a flowery meadow, cycling through a field of sunflowers and even harvesting vegetables. The accompanying text encouragingly informs the reader that gardening naked is “not only a simple joy” but also “fun, costs no money, runs no unwanted risk, reminds us of our tie to the natural world, and does something good for the environment . . .” Having never had any particular desire to garden au naturel myself, I can’t vouch for whether or not it’s a simple joy; I would, however, have to take gentle issue with the claim that it runs no unwanted risk. Putting aside the obvious dangers of alarming the postman, or being inadvertently captured on film by a passing Google Streetview camera, there are more mundane things such as nettle stings and strimmers’ dermatitis to worry about.

The latter, in particular, is a painful, disfiguring skin condition that’s not uncommon at this time of the year, often as a result of the freshly-cut foliage of common hogweed, Heraclium sphondylium (a common plant along Irish hedgerows), coming into contact with the bare arms/hands/face of the person strimming, causing burning and blistering of the skin. More properly known as phytophotodermatitis, it’s caused by certain compounds (“furanocoumarins”) contained in the plant, for which the trigger is bright sunlight.

Having suffered from this condition myself a few years ago after strimming an overgrown ditch (fully dressed, by the way, but gloveless and wearing a T-shirt), I learned a painful lesson. Now I try to strim only on cloudy days and always cover up when I do so (long sleeves, trousers, gloves, boots, a visor).

A tall plant with pinnate leaves and white, umbelliferous flowers that appear between June and September, common hogweed is the smaller relative of the better-known and much-feared giant hogweed; both belong to the Apiaceae/Umbelliferae family, a group of plants notorious for causing skin reactions among some sensitive individuals. Other wild flowers that belong to this plant family include cow parsley, hemlock, and the wild carrot. Cultivated relatives include parsnips, celery and parsley, and there are similar recorded instances of some sensitive people suffering blistering and burning of the skin after handling the foliage of these plants.

In fact phytodermatitis (the technical term for a complex range of skin conditions caused by contact with a plant) is an occupational hazard for gardeners, florists, nursery workers and others who regularly handle plant material. Worse again, the number of plants known to cause these conditions in a small but vulnerable percentage of people is surprisingly large; the long list includes many members of the very large Asteraceae/Compositae family such as chrysanthemums, dandelions, sunflowers, cosmos, helichrysums, echinacea and English marigolds, as well as daffodils, tulips, primulas, erythroniums, alstroemeria, pelargoniums, rue, box and ivy.

One well-known sufferer is British gardener, Beth Chatto, who in a letter to her friend and fellow gardener, the late Christopher Lloyd, sadly bemoaned the fact that she was forced to always wear gloves while gardening.

“I hate wearing these but since I became allergic to most plants in my mid-40s, a mild attack, as I have now, of itching little water blisters, should be enough to warn me,” she wrote.

In the case of Dr Matthew Jebb, director of the National Botanic Gardens in Glasnevin, it’s a particular sensitivity to the leaves of Rhus typhina, more commonly known as the stag’s horn sumach tree; a small tree/shrub that is a member of the Anacardiaceae plant family and whose fiery displays of autumn foliage are a very common feature of many Irish gardens. Jebb first became sensitised after a plant-hunting expedition to Papua New Guinea some years ago, where he came in regular contact with some closely-related species.

“Now I can’t touch a single sumach leaf without coming out in a horribly painful rash,” he says.

Less common plants also pose a risk, as organic gardener Nicky Kyle recently discovered. Particularly taken by a handsome specimen that appeared as if by magic beneath her bird-table, Kyle was horrified to eventually discover that it was none other than the non-native Ambrosia artemisiifolia, or ragweed – a noxious plant whose pollen is a well-known hay-fever allergen and whose foliage, if handled, can also cause allergic contact dermatitis. It had grown from a seed that was a contaminant of the particular birdfeed mix that she was using.

The moral of this particular tale? You’ve probably guessed it but if not, I’m going to gently spell it out. Best to cover up . . .

This week in the garden

Finish pruning spring shrubs (kerria, forsythia, flowering currant)

Start to move summer bedding plants into their final positions outdoors

Protect plants against slug and snail damage (try iron-based slug pellets, Nemaslug, beer traps, hand picking at night)

Sow maincrop carrots, lettuce, peas outdoors while more tender plants (courgettes, pumpkins, sweet corn, French beans) can be sown in modules under cover

Diary dates

The RHS Chelsea Flower Show kicks off next week (22nd-26th May, rhs.org.uk), while the inaugural Chelsea Fringe garden festival begins today (chelseafringe.com) and continues for the next three weeks

This weekend also sees the launch of the first ever Herbfeast at the Organic Centre in Rossinver, Co Leitrim (Saturday, May 19th to Sunday, May 20th). For details, check out herbfeast.ie or communityofirishherbalists.ie

This is the second day of Ireland's BioBlitz 2012, which is being organised by the National Biodiversity Data Centre, in association with the OPW and other partners. Four teams assembled at State properties across Ireland will be competing to see which site can record the most species of wildlife over a 24-hour period. Full details of BioBlitz can be viewed on the BioBlitz website, bioblitz.biodiversityireland.ie

There will be a plant sale (including many lovely lilies) at Trudder Grange, Newtownmountkennedy, Co Wicklow on Friday, May 25th and Saturday 26th (10am-5pm) in aid of the Cystic Fibrosis Research Trust