Blooms amid the Bolly and the B-list: it's the all-new Chelsea

The Chelsea Flower Show is not just about flowers - it's about designer gravel, creative landscaping, corporate hospitality and the ubiquity of Alan Titchmarsh.

The Chelsea Flower Show is not just about flowers - it's about designer gravel, creative landscaping, corporate hospitality and the ubiquity of Alan Titchmarsh.

The reinvention of gardening as a commercial goldmine is well advanced. And so the show, which opens today, is no longer chaps in linen and gels in wellies sipping Pimm's and admiring the blooms - it's about garden-paving companies sponsoring displays based - strangely enough - around lots of paving, and inviting a few of their celebrity "friends" to help knock back the Bollinger. There were more B-list celebrities at Chelsea yesterday than you would be likely to find in a casting queue for the next Celebrity Big Brother.

Look: there's Christopher Biggins and Leslie Joseph "toasting'' the National Association of Floral Arrangement Societies. But wait, there's Liz Hurley at the Raffles Thatched Gardens Buildings stand, with "her friends the Duke and Duchess of Rutland, who have recently had a Raffles summerhouse installed at their home at Belvoir Castle''. And why Cilla Black was at the Barbados Horticultural Society's display is, frankly, anyone's guess.

But it was Alan Titchmarsh, housewives' favourite and king of the makeover, who was everywhere - opening a stand here, and fronting a BBC live broadcast while standing on an imitation bridge over there. One press release was headed: "Alan Titchmarsh - a strange new hybrid''; well that's their opinion, and if you couldn't get him there was always Eamon Holmes. But somehow he doesn't have the same cachet in these circles.

If you were not following the rent-a-celebs, the other thing around every corner was a water feature. In fact, there was probably more water than flowers. It was cascading out of nymphs and shepherds, running - attractively - over glass and every manner of stone, spraying out of elephants' trunks and trickling down sundry bits of artistically composed scrap metal. It was also intermittently pouring off the roofs of the marquees, but that was more to do with the weather.

Chelsea is not really about gardening as normal folk understand it. It's about fantasy gardens to admire more than replicate - rather like consuming the offerings of three-star chefs which you would never attempt to copy in the kitchen. That's why the gardens are called things like "Oasis of Ruin'', "Sensuality'' and "Inner Retreat''. "The Hasmead Octopus Garden'' was opened, of course, by Ringo Starr.

And while the true meaning of the "Merrill Lynch Garden'' is quite clear, it remained obscure as to why Southend-on-Sea Borough Council's parks department had chosen to recreate the kind of garden which a railway signalman might have had in the 1960s, complete with signal box.

The Royal Horticultural Society, which organises the show, stresses that, behind all the showbiz, this year's event has serious themes: recycling materials, biodiversity, climate change and such environmentally friendly ideas as covering roofs with grass and plants - that last one must have been the reason for the two turf-topped Minis seen heading towards the King's Road.

But what garden trend-setters really need to know is what's in this year - what's hot among the gravel and gardenias. According to the Society, something called Ophiopogon planiscapus, otherwise known as Black Grass, is booming and this year's show sees the unveiling of Sambucus, also known as Black Lace, which has been bred by the Horticultural Development Council to have black leaves and stems, and pale pink flowers. It seems that, when it comes to gardening, this year's black really is the new green.

Philip Harkness, purveyor of English roses, says that times have been hard since gardening became another lifestyle makeover programme. So Chelsea is in a bit of a crisis, he says. "It's not a horticultural show any more, it's an event, isn't it? And I am not sure how helpful it is to the average gardener. But that's not what it's all about, is it?"