Restaurants, it occurs to me, are like plants. If that sounds a little bald, let me elaborate. Some behave just like my annual attempts to grow basil: they pop up, full of enthusiasm for life in general and their own in particular, and then shortly afterwards, feeling the chilly winds of adversity, they keel over. Mostly though, restaurants grow organically, gradually establishing a reputation and gaining a loyal customer base. They grow, they flourish, just like hardy annuals, but rarely exceed a life-span of twenty years. And lastly there's another type - reminiscent of the ground elder - that once established seems impossible to eradicate. Invasive and vigorous, it single-mindedly kills off its competitors until it has cornered its own patch of territory, supplanting all else with its version of fast food. With luck, there will always be room for the others before the nightmare vision of mono-culture gastronomy becomes a reality. And if you're wondering why this lengthy analogy, it's simply because I took my son to the Blue Orchid, whose floral name partly prompted this line of thought. The other reason is that it occupies the place once held by another restaurant, now closed.

After four years in Florence studying portraiture my boy is back home, about to embark on that complicated business we call a career. Clearly being well-nourished is a good start for that endeavour, so we set off for Blackrock and our Thai meal, pausing briefly to visit Gill Hall, who lives nearby. Since she is an aficionado of Thai food and was eager to try out her new local, it didn't take much persuading to get her to accompany us, and so we were three.

The basic shape of the restaurant is much as it was when it was Japanese, but there's a new circular window opening onto a small private dining room, which you can peer into from the car park, much as into a goldfish bowl. The main room is long, painted in soothing and neutral pastels, with framed pictures providing the splashes of colour for contrast. The tables are large enough that you don't feel cramped; the seats are comfy; the cutlery, tableware and glassware gleam with sparkling newness. We were shown to our table in the centre of the room and while my guests began exploring the menus, I went through the wine list.

The list is priced mostly in whole or half euros, so the prices must have changed since they were in pounds, whether up or down I can't tell. It's reasonable priced, not overly long, but it does include some of the stalwarts of restaurant lists; Jamieson's Run, Santa Rita, Louis Latour and Faustino - all fine ranges, but perhaps it makes the list a little unimaginative. I chose the Santa Rita Chardonnay at €21.50 for Gill and myself, while Rocco decided that the Singha beer at €4 was for him. The menu begins with thirteen appetisers and soups, which range in price from €5 to €16, although this last, the Lard Prik, is for two people. Main courses include pork, duck and beef dishes, there are noodle dishes, seafood dishes, and vegetarian dishes as well. I won't give you those long, single syllable Thai names for the dishes, but between us we picked vegetarian spring rolls for Gill, pork and crab rolls for Rocco and a duck salad for me as starters. For the main courses Gill chose the vegetarian Phad Thai; Rocco, ever a man for red meat, went unerringly for the sirloin steak, and I chose the crunchy asparagus which came with slivers of spiced beef.

Although the restaurant was fairly full, the service throughout was attentive and friendly - they were even prepared to change the background music for Gill until I intervened and reluctantly admitted that I quite liked 'Sweet Caroline' by Neil Diamond. This earned me no points for street cred with Gill, who cringed, but let me hear it.

I'll admit to yet another prejudice; I'm not crazy about the taste of coriander leaf and it does tend to turn up a lot in Thai cookery, but if it was present in any of the dishes I tasted that night, it was blended with other tastes in such a way that it didn't affect my enjoyment of the meal. We all tasted and shared, although Gill ate no meat. The starters were tasty and well presented on plain, square plates which I liked; my duck salad combining flavours in an interesting way. The various rolls that Gill and Rocco had were presented in the upright fashion, cut at an angle.

Thankfully we had a large bottle of water on the table, because my first taste of my spiced meat left me literally speechless. A piece of chilli caught in my throat and I could almost hear it saying 'now I've got you, whitey' as it burned me. Slowly my voice came back with the administration of water and I carefully continued, discovering with pleasure that the rest was not as hot as my first mouthful. There were no such dramas with either Gill or Rocco, who were both delighted with their choices. Egg-fried rice and noodles accompanied the main courses.

These were large and filling platefuls and none of us were left with much of an appetite, but we did choose a dessert between us, a plain and simple bowl of peeled lychees. Rocco had an Irish coffee instead - the drink that provides in a single glass all four essential food groups: alcohol, caffeine, sugar, and fat. A decent espresso finished the meal for me and the final bill came to €128.75, or if you're still thinking in old money, about a hundred pounds. Good food and good value - I'll be back.