Gardening: The danger of obsessive love affairs: Stephen Anderton argues that gardens need a creative approach rather than the compulsive collection of rare species

I CONFESS to having an extinct passion for irises and to having had more than a passing affair with geraniums. There was a time when I would willingly have called Geranium sinense a wonderful plant. It has fabulous nodding maroon flowers, which drip cherry and pink stamens. But let's be honest - they are minuscule; their effect in a garden is negligible.

Many gardens in Britain are becoming, to their detriment, plant collections above all else. There is a vogue for rarity in plants. Gardeners are content to have a plant in the garden simply because it is different - an obscure species, or a dwarf form, or one with slightly larger flowers.

Gardens open to the public like to boast that they have a 'national collection' of a particular genus, because it gives them street cred among the gardening public. True, plants in the wild and those bred in gardens need preserving. They are our working palette as gardeners. But does a collection really do much for a garden?

There is a danger of confusing conservation with active gardening, which at its best is creative, innovative, above all selective, and frankly brutal to the things it rejects. No doubt our ancestors, from time immemorial to the Victorians, would stand amazed at our actually feeling sorry for nature, which was so cruel to them. We may have done some awful things to the natural world in the past 60 years, but to pity nature is a bizarre departure for any form of life.

It is partly this passion for collecting plants, like stamps, that leads to theft in gardens. Not just cuttings, but also whole plants disappear. Tellingly, the label often goes too, as if it were a guarantee of the thief having stolen the true species, proof that it is a designer item.

Theft becomes especially galling when one plant from a group is stolen, as though the thief were saying: 'Oh well, plenty left there]' True, you still have the plant and can repropagate. But the theft denies what you as a gardener have been trying to achieve. You plant a block or group of plants because you are doing something with them - making pictures or plant associations, call it what you like - not just pinning down a specimen in a collection.

Even creative gardeners in their early years go through the trials of addiction to particular groups of plants. If only there were an inoculation against it. Collecting has its value, of course. Research collections in botanical institutions are a priceless resource. Collecting is an excellent way of learning about plants, and forces us to look at things in detail.

But it can also blind us to the faults of the plants we love. If you are genuinely infatuated with a genus, you can willingly overlook the fact that a particular variety always flops just as it is about to flower, or has next to no perfume when all the others do, or is simply dull. But people in the grip of addiction will be the first to admit that it is hard to resist - 'Oh well, I haven't got that one, so I suppose I'd better have it.'

And then the inevitable cry goes up: 'Where am I going to put it? There's no room in my garden]' Ah, but in it goes.

If you are going to have a good garden, you need to be a little more ruthless. Gardening is, as well as picture- making, a kind of keeping the peace. The difference between a garden and the wild is that someone is there keeping at bay those plants with territorial ambitions, and allowing more delicate treasures to flourish.

It makes no difference whether you garden formally or have the most romantic of wild gardens, the gardener is still there to be the interventionist; only the rigour and frequency of the attention varies.

There are gardeners who do not enjoy having to keep the peace, and ban vigorous or tall plants entirely. These are the gardeners who go for labour- saving heathers and conifers, grow every plant in a quarantine of bare earth, suspecting that plant association is something that leads to 'social diseases'.

The good thing about being the peace-keeping force in a garden is that the picture develops exactly as you want it to. You decide what to plant, you negotiate the deal between obtaining the best-looking plants and the maintenance time available.

Will a good garden really have time for passengers, plants whose rarity outstrips their usefulness and attractiveness? Even a plant that is only a foil to others can be attractive. We need to develop more selectivity towards plants, choosing only those that serve our aesthetic purposes.

Think, too, of the money. Fashionable addictions are manna to the specialist nurserymen, who in the past 10 years have done an important job in making available again so many good garden plants. But do they not sometimes smile at their customers' apparently endless desire for new geraniums and new hostas?

It is comforting to see, however, that among keen gardeners there are those who grow out of collecting and are content to see plants they might once have coveted now growing happily in other people's gardens.

Gardeners sometimes reach a further stage - the nirvana of gardening - in which they prefer to see plants growing freely in the wild. In this respect, I like to think I am gradually becoming my own man. Yet seeing sheets of Geranium sanguineum in the short turf of the seashore near Berwick recently, I felt a stirring of the old lust. It soon passed, however, and I began to see why serious gardeners are so often middle-aged.