Bright spark: As autumn approaches there is one firework of a flower that really catches the eye

A little curling fountain of pink firework sparks, each flower head is made up of a studded set of tinier flowers, a bit like a Barbie-toned Agapanthus. There are only a few floral highlights at this time of year, but among them are the prettiest, frilliest and slightly pink-spidery of early autumn treats, the Nerines. The name sounds mythological, but it turns out nobody's really sure. Apparently it was a cheeky Regency vicar, the Rev William Herbert, who coined the name, possibly just out of his wonderful head.

But really the greatest thing about them is when they flower – right now, on soft, foggy mornings when everyone else is getting out the leaf blower. There are 30 or so species in the wild, but horticulturalists have been working hard since the plants were first imported from South Africa to widen the range ever more expansively.

There are two broad divisions: first, the ones that can just about stand a British winter outdoors. Nerine bowdenii is a favourite, especially in the West Country (it was the appropriately monikered Cornish Bowden who first brought them to the UK in 1903). But for much greater, naughtier, pinker variety, have a look at the indoor, tender species, the star of which is Nerine sarniensis.

I was reminded of the breadth of possibility on Planet Nerine while flicking through a new book, Clondeglass, by Eire's favourite gardener and RTE staple, Dermot O'Neill (£25, Kyle). The book is a record of O'Neill's eponymous garden, which is a decade-long work of restoration, but it focuses very much on the things he actually grows, plantsman-style, with quite a few pages devoted to this spectacular October flower.

O'Neill's passion for Nerines predates Clondeglass: "I went on a trip with my father to look for interesting plants that were not available in Ireland at the time. On my travels, I came across some exciting old Irish cultivars of Nerine." This rediscovery of traditional Irish varieties is something of a theme for O'Neill, who enthuses about an older generation of Eire plant breeders. He cites the wonderfully named Miss Doris Findlater, who spent the late 1950s and early 1960s breeding such also-wonderfully-named Nerines as "Glensavage Gem" and "The Spider".

As far as O'Neill's collection goes, I'm most tempted by a tender Nerine in deep, velvety damson, called "Uganda", although I think I could also be swayed by "Brighton Rock". However, then we get to the annoying bit: these more unusual Nerines are practically impossible to buy. Beth Chatto has a small range, stocking at planting time outdoor N.bowdenii as well as N.undulata, a white floaty thing (both £4.20, bethchatto.co.uk).

But for N.sarniensis varieties, you may have to go on the rampage. Either that or join a specialist society: the Nerine & Amaryllid Society charges £12 annual membership, and has regular meetings, and it was through its website that I found my way to nerines.com, which lists for sale a number of the varieties grown at Exbury Gardens, Hampshire, from the Rothschild collection. They ain't cheap: a "Starter Collection" of 10 varieties is £70. And "Uganda" comes at a princely (though still tempting) £18.50 per bulb.

Getting hold of them, though, is just the first stage. Tender Nerines require specialist care. At Clondeglass, Dermot O'Neill has a perfect little greenhouse constructed just for these tender-hearted African immigrants. Painted in an elegant grey-greenish-blue, it sets off the range of pinks spectacularly well.

Quite apart from tasteful colours to paint your greenhouse, O'Neill has advice on more practical matters. Let leaves and flower stems die back naturally, to allow the bulb to gather back in all their goodness. Feed them, when in full growth, with an organic tomato fertiliser. And never leave them sitting around in water. These bulbs need sharp drainage and plenty of sunshine or they will simply rot away.

There is one more trick you need to know to get flowers from an indoor Nerine: they require a proper dry season, starting in April, giving just enough water to keep the roots alive, through till September, when weekly watering should recommence. Expect flowers a few weeks later, bursting forth without a leaf in sight. A rare delight indeed.