A botanical note has taken root in the restaurant world. Floral monikers are all the rage. Down south, there's Arbutus and Hibiscus; in Glasgow, there was Amaryllis. In Edinburgh there is Tiger Lily and now Iris, a hip new restaurant that has germinated amid Thistle Street's throng of eateries and posh boutiques.

As with Tiger Lily, Iris delivers the trendy interior design that gives Edinburghers faith in a dining establishment, even if the food isn't up to much. At Iris, this time we're looking at a retro, 1950s vibe with Mondrian-ish floor coverings, wood effect walls and abstract or vaguely botanical wallpaper.

It's all very smart and comfortable. The staff give you a warm welcome. And if all you want is a fun night out, a bill that isn't too frightening because the wine is cheap, and something plausible on your plate, then you might like it. But the food isn't much cop, there's little evidence of thoughtful buying, and the menu is pretty dated; the sort of clichéd, copycat thing you'll find in provincial brasseries throughout the UK. The cooking aptitude is basic and the kitchen seems to have a dependency on humdrum salads - to pad out the main element of the dish - and cream as an instant fix for sauces.

Our starters were pricey and disappointing. I wouldn't have quibbled about paying £8.90 for scallops had they been any good, but these were water-bloated, jelly-like specimens with only the most dilute taste. The night before, I had dined at Andrew Fairlie at Gleneagles, where the scallops were exemplary: sweet, crisp-fried and with that likeable resistance in the mouth that flags up a truly fresh bivalve. As the top place in Scotland, Gleneagles was always going to be an unfavourable comparison, but Iris's scallops were even worse than most. An extraneous slice of cured, dried ham and a wad of frisée endive in an aggressively acidic vinaigrette added insult to injury. And at £5.90, a disc of deeply average puff pastry smeared with pesto and topped with cherry tomatoes, perched upon a routine hill of rocket, represented money for old rope in cooking terms. It was the sort of thing you could easily knock up at home.

The menu wasn't explicit on the point, so I'm guessing that my halibut was farmed because it manifested that odd combination of dryness and wateriness I associate with farmed fish. It was to come with sweet and sour dressing and spicy salad, which turned out to be another pile of indifferent greenery in a saccharine-sweet dressing. To make matters worse, we had been intrigued by the Vietnamese side salad - it turned out to be another heap, this time of cheap beansprouts and Chinese cabbage, doused in a ludicrously sweet dressing with only the faintest hint of fish sauce and under-powered chilli.

We were assured the chicken was organic, free-range, corn-fed - and it seemed decent enough. It was meant to be stuffed with langoustines, and indeed there was one prominently ensconced on top, but the filling tasted much more like those tough, chewy farmed tiger prawns than our prime, succulent wild Scottish crustaceans. Its "garlic and herb buerre sic blanc" read unconvincingly even had it been spelled correctly: no true beurre blanc contains garlic. It tasted less like an emulsified sauce than a load of double cream flavoured with old garlic.

Having started off well, the service slowed down to a snail's pace, as if the kitchen couldn't keep up with the pressure of orders when tables started to fill up. And the desserts were barely worth the wait. A warm, likeable orangey-chocolate brownie was let down by its puff of over-aerated cream. A scoop of good crème fraiche was what it needed. The same creamy float did nothing for a fridge-cold, sickly-sweet poached pear with an oddly squashed shape, possibly acquired in storage.

Call me cynical, but despite its faults, I bet that Iris will do very well in Edinburgh which, when it eats out, is currently transfixed by style over content. Oh, for a breath of fresh air and a new eatery that marches to its own tune. Save for Tom Kitchin in Leith, the capital is back in the foodie doldrums again.