A couple of years ago we did a brave and foolish thing. We took the top of our house off and plonked a conservatory onto it. At first, when we were still in the Constant Leak stage, it looked as if we should be considering aquatic and marginal plants. The cheerful yellow monkey flower, Mimulus guttatus (which grows wild in the Dodder river), and the lovely drumstick primula, P. denticulata, would have found a congenial habitat in our watery glass room. And the carnivorous Sarracenia, or pitcher plant, would have been especially welcome when certain of our builders called.
But when the interior downpours were stemmed we found ourselves with an Arid Desert zone in our mainly south-facing folly. To be sure, it was wonderful for boosting the growth of half-hardy plantlets in early spring, but it became a frying pan thereafter until the onset of autumn chills. So, being an ardent believer in suiting the plant to the environment, I gathered up all the succulents and cacti that had been sitting stolidly around on dusty window sills and brought them up to our boiling eyrie.
I - and they - have not looked back since. Our conservatory is a cactus-and-succulent heaven, with members of its prickly congregation growing taller, fatter and healthier, and celebrating their new home by breaking into an annual rash of startling flowers.
It strikes me that all over the country there are underused sunrooms tagged onto houses. Some (like ours) were built in a fit of madness, others were acquired for a few thousand quid extra when a new estate house was bought. In these conservatories, however, especially those that face south, the plant life often consists only of a parched spider plant, a scorched peace lily and one or two other abandoned plants. What a different picture would be created if people brought in some cacti and succulents (Atlantic Homecare shops have lovely ones from Abbey Brook Cactus Nursery in the UK), and allowed their bristling, architectural shapes to decorate the room.
And what is the difference between a cactus and a succulent? Janet Wynne, the chairman of the Dublin and District Cactus & Succulent Society (DDCSS), tells me that cacti can be distinguished by the "areoles", a small cushion of hair around each spine. And all (bar one genus, she says) are natives of the New World. They occur from the furthest tip of South America right up to - incredibly - Canada, with Opuntia polyacantha and Coryphantha vivipara living in British Columbia and Alberta, where they lie buried in deep snow all winter. Succulents, meanwhile, live all over the globe, and many - like the agaves of America, and the aloes of Africa and the Arabian pen insula - are very familiar to Irish plant-lovers. Starting a collection of cacti and succulents is as easy as anything. Most are forgiving of periods of neglect or, on the other hand, over-exuberant attention (which makes them ideal for eager young gardeners). Janet Wynne suggests that the novice cactophile and succulent-enthusiast might begin with agaves (while being sure to respect the vicious points on the leaves), aeoniums (which grow into miniature, other-worldly trees bearing fleshy blunt leaves), rebutia (quite small, but effective planted en masse in a bowl), and mammillaria, crassula and echeveria, all of which grow large quite quickly. Most of these can be picked up at plant sales (like the one at the DDCSS's first-ever annual show tomorrow) or in the shops.
Janet Wynne, who recently took early retirement from RTE, is busy propagating stock for a new cactus and succulent business - with the sure-fire name "Wynning Plants" - to be launched in the next year or two. Her own collection contains around 800 varieties. Among them are a crazily-coiffed Oreocereus, its sharp spines covered in bad-hair-day white tresses (it's also known as the "old man of the Andes"); a columnar Notocactus leninghausii, which grows in grassy savannah-land; all sorts of succulent euphorbias (the hot climate versions of our garden spurges) - and about seven-hundred-and-something other types.
All are grown in John Innes No. 3 compost mixed with at least the same amount of grit or sand, and the odd bit of perlite for aeration. Acid-lovers get "a drop of peat", while lime-lovers (which mostly have white spines or fur) have a few lime chippings added. Flowering is aided by two or three feeds in spring and summer, and watering happens during the growing season only when the pots dry out - and is practically non-existent in winter. What could be easier?
And, finally, a special cactus for the family conservatory is the supremely shapely Echinocactus grusonii, which grows into a large corrugated pouf studded with honey-coloured hard spines. In the nicer shops, like Atlantic Homecare, they call it "the
golden barrel cactus", but somehow I think they'd sell more if they used its other name: "the mother-in-law's seat." And just so you know: Janet Wynne says that the best way to remove wayward prickles from the human body is with a roll of sellotape.
The DDCSS show is on tomorrow from 10 a.m. to 4 p.m. at the parish centre under Our Lady of Dolours Church, Glasnevin, Dublin. Admission £1. Further information on cacti and succulents, including details of the DDCSS, can be found on the Internet at www.cactus-mall.com