Gardening: A rose by any other name just won't do: Anna Pavord finds some exquisite French bloomers, but has trouble tracing the same varieties to plant in Britain

My education in French enables me to hold my end up reasonably well in a discussion of Lamartine's verse forms or the philosophy of Sartre's Huis Clos; but it did not fit me for an encounter with the gardeners in the stupendous rose garden at Bagatelle, Bois de Boulogne, on the outskirts of Paris.

The roses growing on screens, tripods, pillars and arches were all beautifully tied in with small knots of what looked like vine. 'Du vin? Du vin?' I demanded, indicating the neat, woody ties. I couldn't remember vigne, for vine. The group of three gardeners backed off, evidently thinking they had a crazed alcoholic on their hands. Fortunately, an intuitive old man passing by saved the day. No, he said in careful, slow French. Not vine. Osier. Willow.

You would need thin, sappy pieces of willow if you were going to try this trick yourself. The French favoured reef knots, neater than grannies, and, having secured the rose to its support, then trimmed the knots so that there were no loose ends. The effect was enchanting. The ties were also durable and very easy on the eye.

The rose garden, laid out in a formal series of box-edged beds, was the brainwave of J C N Forestier, then chief curator of parks and gardens in Paris, and was made in 1906. The guidebook tells you that there are 9,000 roses in it, climbing, sprawling, splayed against treillage, swinging on swags of thick rope.

For a foreigner, the only unfortunate thing is that you come away from Bagatelle with a notebook crammed with the names of excellent roses you have seen there, only to find that they are unavailable in your neck of the woods.

One of my own favourites was a shrub rose, 'Denise Grey', raised by Meilland in 1989. The overall shape of the shrub was good, the leaf was an interesting greyish green, the flowers pale pink. They were still smothering the bush in the third week of August. It had won a gold medal in the Bagatelle trials.

As it was not listed in the encyclopaedic Find That Rose, I contacted the Royal National Rose Society, which put me on to Lathrope Roses, Meilland's agents in this country. They said it had never been introduced here, though even that was hard to confirm, as roses are renamed with muddling frequency, either by their raisers or by the agents who introduce them into different countries. Lathrope's suggested I tried 'Bonica' instead. This is certainly an excellent rose. The colour is much the same as 'Denise Grey', but the habit is much wider and sprawling. It is generally classed as procumbent. The rose I saw was a more upright shrub.

Where the formality would not be out of place, you could get extra height by using 'Bonica' as a standard. Quite a few of the ground-covering roses, such as 'Bonica' and another Meilland rose, 'Swany', make very attractive standards, the growths lax and much freer than the usual Hybrid Tea type. There were some wonderful 'Swany' standards in Bagatelle, covered in small cream flowers. Unfortunately there was no discernible scent. 'Bonica' is only slightly scented.

That is a big minus. The big plus, though, is the long season of flowering. Both roses put up with soil that is on the poor side. Both would look good as standards in pots, provided they were big enough and standing in a place where they would not be blown over by wind.

Ground-cover roses have grown enormously in popularity over the past 10 years. There is a whole flock named after birds, such as 'Grouse', which makes a strong, healthy, if rather untidy sprawling bush that can easily cover 10ft of bank. It has floppy single white flowers, small but with a prominent boss of gold stamens. Both this and 'Pheasant' came from the same cross: 'The Fairy' mated with a seedling of the sprawling white- flowered R. wichuraiana.

Bloodlines of roses are as complex as those of racehorses, but you notice some varieties cropping up repeatedly as parents. 'The Fairy', for instance, is also involved in the cross that made the good ground-cover rose 'Fairyland', pale-pink flowers that are small but double, which makes them seem more important on the bush.

'Fairyland' was bred in Britain by Harkness and makes a low, compact bush not more than 2ft high and perhaps a yard across. The County roses, such as 'Surrey' and 'Warwickshire', are similar in size. 'Bonica' and 'Swany' used as ground cover are much more vigorous. They mound up to perhaps 3ft and spread at least twice as far.

'Nozomi', bred in Japan in 1968 and one of the first of this new race of ground-covering roses, will make a shrub of equal size, with small single pale-pink flowers. It always looks healthy, but does not flower continuously like 'Bonica' and 'Swany'. You get an early summer burst and nothing else.

The multi-coloured roses such as 'Joseph's Coat' growing at Bagatelle struck me as too hectic, too noisy. 'Joseph's Coat' is orange, yellow and deep pink, the old flowers darker than the young. It makes an upright shrub, about 5ft high, and because it never stops flowering is always shouting 'Look at me'. In a small garden it would be irritatingly aggressive.

Many of the original roses at Bagatelle came from Jules Gravereux, owner of the famous La Roseraie de l'Hay rose garden, just south of Paris. He was also the force behind the restoration of Malmaison, the Empress Josephine's garden about 10 miles west of Paris. Here, she made the most extravagant rose garden ever known. Napoleon divorced her in the end, but not because of her spending on her garden. He wrote to her: 'I have allotted 100,000 francs for 1810, as a special sum for Malmaison. So you can plant anything you want and spend the money as you like.' Why does nobody ever write me letters like that?

Find That Rose, which lists the 2,600 roses available in this country together with suppliers, is available (pounds 1.70) from the British Rose Growers Association, 303 Mile End Rd, Colchester, Essex CO4 5EA. In advance of a BBC 2 series in January, Roger Phillips and Martyn Rix have brought out The Quest for the Rose (BBC Books pounds 18.99), which describes their travels in China looking for the ancestors of our modern garden roses.