To be sniffed at: Emma Townshend reveals why her latest obsession is roses

Obsessions come and go in life. When you are young, they tend to burn fast and furious, and then suddenly they are gone: I will never again bore anyone with long, repetitive sermons on the greatness of Breyer plastic model horses, Massey Ferguson tractors or 1980s heartthrob band Haircut 100. But in the second half of life, obsessions tend to creep up. Slow-growing and tenacious, they take hold before you notice. And that is what roses have done to me.

I used to have a perfectly healthy, in-proportion respect for the rose, a good garden flower among many others. Lately, though, I find myself having to sniff every rose in a garden I'm visiting before I can leave. (Which one is the best? Better give them all one more sniff, to be sure.) Or swerving the car to a halt to investigate random roses in strangers' front gardens, wishing people would just be a little bit more organised and leave the labels on, to facilitate me in identifying what it is they are growing.

I'm not even the only 40-year-old spending too much time with the David Austin rose catalogue. At a pal's birthday party, where there were at least four proper, bona-fide, "you could sing all the words of their song" pop stars, I ended up in the corner talking to a friend who spends his working life doing things like headlining Glastonbury. "But we are taking at least a year off," he explained, "and now what I really want is to find a properly deep-red rose to climb up the front of my house." You see?

The reasons for this growing obsessiveness are not completely clear. Roses are long-lived investment plants which repay the attention we give them. But are they really that much better than any other plant? Well, I'm starting to think, yes. There's the perfume. The deep, changing colours of the petals, which can be a rich sunset one day and a pale winter's morning by the next. The great big bowls of the flowers. And best of all (especially since modern rose-breeders such as David Austin got to work), the repeat flowering. Which means there are roses in gardens near me that are still flowering in November.

Right now is the exact time of year to order and plant bare-rooted roses, which is the cheap way to add roses to your garden, as they come with far less of a price tag than ones grown in pots. But you'd need to have spent the whole summer sniffing to know which rose it is that you actually want to order. For now, ponder other important questions: do you want a neat bush, pruned down to a few stems in winter, or a rambling bush that will hide a shed? Do you want a bright, zinging colour, to flash against other strong hues, or a soft, retiring pastel for a more romantic feel? A rose with enormous history behind it, such as the 500-year-old Rosa Mundi, or a recent addition such as Benjamin Britten, one of the best pinky-red roses ever?

Thank goodness we have the rest of our lives to work out the answers.

If you prioritise...

1. The leaves

Roses are mostly about the flowers, but leaves range from spectacular reddish silvery-grey in Rosa glauca, to the freshest green in Rosa canina. Both £14.99 bare-rooted

2. The scent

For me, this is key; any with a light fragrance can be crossed off straightaway. "Princess Alexandra of Kent" is sumptuous. £14.49

3. The flowering

If roses in November are important, look for "repeat-flowering" labels. The "Alnwick" rose is a corker. £13.49

4. The health

"St Swithun Climbing" is a romantic pink with in-built resistance to blackspot. £13.49

All from davidaustin.com