Flowering of orchids is notoriously unpredictable

ANOTHER LIFE:A SPECTACULAR orchid summer! From unmown football fields in Dublin suburbs, grassy plots in Kerry villages, coastal dunes all round the island, come wonderstruck reports of the flowers in huge numbers – shocking-pink pyramidals, marsh orchids in royal purple, other spotted-leaved sorts in every frilly shade between. Down the boreen, on a river bank, cluster greater butterfly orchids, intricate in ivory.

Such an obliging show of most – indeed, possibly all, by the time the season ends – of this island’s species, sub-species and varieties could not have been better arranged for the OrchidIreland survey, run from the Ulster Museum.

And its recorders, amateur and professional, however well briefed in workshops, will be pleased to have handy The Orchids of Ireland, the new book that offers the last word (at least for now) on their notorious variation.

The spotted orchids, particularly – dactylorchids, as they’re known – are so prone to shades of difference in size, flower colour and leaf-marking that the number of their species is still not agreed and experts grow vehement in discussion. A misfortune was the failure of the late, great painter of the island’s orchids, Raymond Piper of Belfast, to publish the work of some 40 years because, in his study and portraiture of individual flowers, he could never find an end.

For all his fieldwork, his scrupulous peering through a magnifying glass at every detail of orchid engineering, every nuance of labellum, rostellumor epichile, Piper was not a professional botanist, nor had the scientist's necessary cool. Dr Tom Curtis, on the other hand, author of the new orchid book, brings a certain resignation to his own lifelong passion for the plants. "Within the species found in Ireland," he writes, "it has to be accepted that some individual plants in any one population may never be assigned with certainty and even experts may be unable to give a definite name to certain specimens." His own list of Irish orchids runs to 44 species, subspecies and varieties, and getting on for half with Dactylorhizain their name. The marsh orchids alone show dramatic differences, their luscious flower colours precisely rendered in Robert Thompson's photographs. As for the leaves of dactylorchids, it is "spots like those of a leopard or merging fields of dark pigmentation," says Curtis, that most often point to the hybrid plant. Sorting them out can make the specimens of a sunny coastal dune-slack "dactylorchid heaven or hell, depending on your point of view". His book is backed by more than 35 years of fieldwork, many as chief research botanist with the National Parks and Wildlife Service. But while this gives its pages a sober authority, it is also intended for the amateur orchid enthusiast, with helpful maps and splendid habitat photographs as guides to where species can be found.

Most of them like calcareous or neutral ground, with very few in the acid habitats of heaths, bogs or mountains. And while one might expect ancient refuges to provide the most excitement, the disturbed ground of quarries, road embankments and motorway margins can show dazzling thousands of blossom spikes – some compensation, as Curtis notes, for destruction of ancient, lime-rich eskers in excavation of sand and gravel.

The most exotic-looking orchids are not always the rarest. The tall and beautiful marsh helleborine, for example, is locally quite frequent on limy marshes in the midlands, sometimes in many hundreds. The frog and small orchids, on the other hand, and the Irish lady’s tresses, all rare and protected, are miniatures best appreciated on hands and knees.

Along with their often tricky colourways and swapping of spots, the unpredictable flowering of many orchids is notorious. The glorious bee orchid is the best-known example, often lying low for years and then raising thousands of blossoms with bright pink bracts and bee-dark hearts (for all its insect mimicry, however, Curtis reports that, in Ireland, where this species is at the edge of its climatic range, it usually pollinates itself).

Orchids use underground tubers for food storage ( orchiswas the ancient Greek name for testicle, which the tubers often resemble) and the growth encouraged by last year's long summer rains may have salted away the energy for this year's prodigious blossom.

After many generations of speculation and research, the reasons for irregular flowering of orchids remain complex and inconclusive, and quite probably vary between species and their growing sites. Tom Curtis, having so much more useful to say, notes the phenomenon and moves on.

Details at habitas.org.uk