Show time: Anna Pavord casts a critical eye over the best (and the worst) of this year's Chelsea Flower Show

What happens to Alan Titchmarsh between one Chelsea Flower Show and the next? I was thinking about swallows and their migrations while at Chelsea this year, and there suddenly in front of me was the Titchmarsh, bright and dapper, being powdered and lacquered for his next showing in front of the Chelsea television cameras. Absent from my mind since last May, here he was again with his Permatan nicely buffed up, his pink-shirted chest glowing out between the lapels of his darkly tailored suit. But where's he been? Does the BBC wrap him up between-times and put him safely away in a drawer scattered with moth balls?

Could Chelsea continue without the Titchmarsh? Now that's a serious question. Much more serious than the fact that there were only 13 show gardens this year. A garden doesn't really exist until the Titchmarsh has alighted in it and sung his song. Perhaps the entire Chelsea Flower Show is made now just for the telly, the virtual experience being, for many, so much more real than the real thing.

Still, real was the vast fig tree growing a hundred yards from the entrance to the show, by the corner of Chelsea Bridge and the Embankment. I've never seen such a fig: immense silvered trunk, superb great leaves of buffed green leather and more fruit than I've ever seen on a fig tree. Self-planted, I imagined, as I watched its lower branches tugged downstream by the current. Unpruned. Untrained. Profuse. Generous. Full of beauty.

Gardens need to be beautiful too, and that was what I missed at Chelsea this year. There were plenty of worthy gardens, some slick gardens, some opportunistic gardens, but too little beauty. Designer Ulf Nordfjell's garden won Best in Show but it was as cold as a Swedish winter. No heart. No soul. An icy palette of plants. The rocks he'd used lay like fallen gravestones, hard-edged, slabby pieces of granite. Trees are one of the most important features of a show garden, but Nordfjell had chosen grey willow-leaved pears (Pyrus salicifolia 'Pendula'), then savagely reshaped them into narrow, sparse cylinders. They didn't earn their prominence. There was a good pine tree though (Pinus sylvestris 'Watereri'), used boldly in the front. But the pine had been clipped in a way that enhanced its natural form – dense, rounded, compact. The pear hadn't.

Nordfjell and the Italian designer Luciano Giubbilei were the two biggest players at Chelsea this year, and their gardens sat next door to each other on Main Avenue. This was Giubbilei's first Chelsea garden and he had to come to terms with the unusually tall stilt hedge of hornbeam which Nordfjell had used along the divide between the two plots. The hedge was much too narrow – it wobbled like jelly in the wind – but Giubbilei used it well as the first in a series of clipped evergreen blocks descending into his space: hornbeam, then yew, then box, then a lower hedge of box finishing at the edge of a path of beautifully figured travertine blocks. It was a very Italian design in its reliance on evergreen, water and stone. It was killed, though, by its tediously tight symmetry. Beautifully made, but unimaginative, it was the kind of layout you'd expect to find in the courtyard of a boutique hotel. Sophisticated, but curiously dead.

Like bookends holding together the central conversation pit and its accompanying blocks of deschampsia, Giubbilei included two matched blocks of planting in subdued deep red, bronze and purple: feathery bronze fennel, spires of Salvia nemorosa 'Caradonna', two purplish black bearded iris ('Superstition' and 'Black Swan'), the dark-flowered astrantias 'Claret' and 'Hadspen Blood' and a particularly handsome peony called 'Buckeye Belle'. It was a nice combination, but we've seen a lot of this particular palette since Piet Oudolf and Arne Maynard first used it in the garden they made for Gardens Illustrated in May 2000.

That garden got Best in Show and it deserved it, for it embodied an important shift in gear. So, even more so, did Christopher Bradley-Hole's garden of 1997, perhaps the best show garden that has ever come to Chelsea. Bradley-Hole, an architect by training, was the first person to use modern materials at Chelsea: stainless steel, plate glass, superbly cut stone. That was a massive gear change. It's not that you are looking for novelty. Novelty for its own sake is an empty concept. But each year at Chelsea, you hope you will see something that stops you in your tracks, makes you think, stirs up the passions.

The closest I got to that with the show gardens (only three gold medals were awarded, so nobody can pretend it was a vintage year for design) was when I stood before Thomas Hoblyn's evocation of a bog garden. Evocation was the word. It wasn't ramming messages down my throat. It wasn't pretending to be ecologically correct. Though it used reclaimed materials, sheep's wool, fallen timber, composted greenwaste, road sweepings, furnace ash etc etc, it didn't bore on about sustainability. Hoblyn happily (and very successfully I thought) mixed British natives such as pond sedge, soft rush, common reed and bulrush with plants from North Carolina: stunning stands of American pitcher plants (Sarracenia flava), their huge vase-shaped pitchers glowing in mustard yellow.

After working as a head gardener in Devon, Hoblyn trained at Kew and, as part of his work there, studied the bog plants of Carolina. I didn't know this when I first saw his garden, but it explains to some extent why I believed in it. It started from the right place. It was wonderfully calm, and the planting, though restrained, was full of texture and detail. Though the prevailing colours were mustard yellow (the sarracenias) and blue (from iris) he had scattered in a few drifts of North American columbines (Aquilegia canadensis). That was a master stroke. They are taller, airier than our own aquilegias and the soft yellow and red of the flowers gave just the right amount of complexity to the planting. After his much smaller Urban Garden won a Gold last year, Hoblyn may be disappointed with this year's Silver (I thought he deserved better) but I'm sure I won't be the only one who remembers it as a shaft of heart and beauty in a year when we need it most.