VAL BOURNE says autumn-flowering perennials are ideal for this time of year

I called in at Waterperry Gardens, near Wheatley, to see the nursery is bulging with good plants and I'm delighted to say that not many of them were in flower. Go to most garden centres and most things are. For it seems that many will not buy a plant unless it's bedecked with a bloom.

But why buy a plant that is already at the peak of perfection? Is there pleasure in watching it decline?

It's much better to buy a plant in leaf, one just starting out on its journey and May is an excellent month to plant. The soil is still fairly moist and it's warming up well too.

It's a particularly good time for planting autumn-flowering perennials and dubiously tender plants like fuchsias, salvias and agapanthus. Plant them now and they will make good roots and come through next winter.

Phloxes are in good supply and I can recommend a pale-pink called Monica Lynden-Bell' and a recent white, scented phlox named David'. The latter was the American Perennial Plant of the Year 2002. The foliage is greener than most and the heads of white flower keep going for weeks. It is a very special phlox indeed. Border Gem' is a lovely deep-violet variety that I like, too.

Phloxes can be demanding because they enjoy cool moisture at the root, so they won't flourish in very hot, dry places. Place them in a position where they only get late-afternoon sun and this will suit them well. Then they will avoid mildew, which is a water-stress disease.

Phloxes also tend to lose vigour, often due to eel worm. So be prepared to divide them and move them regularly, usually as they come through in early spring. Their domed heads mix well with asters and most are American prairie plants with a liking for moist soil.

However, there are European and hybrid asters that are more drought tolerant. They include a specially bred hybrid first crossed by Prof Frikart in Switzerland about 1918. His hybrids - between the Italian aster A. amellus and the Himalayan species A. thomsonii - are all named after Swiss peaks.

Aster x frikartii Monch' is the most famous but there is also a Jungfrau' and an Eiger'. Monch' is the longest flowering aster I know. It can start performing in July and still be going strong in October. So this is the desert island selection if you only want one aster. The finely-rayed, large daisies are violet-blue and the foliage is dark-green.

Alan Bloom also made the same difficult cross with his pink Flora's Delight'. All are excellent at the front of a border.

The lower-growing Aster amellus has several purple varieties and Violet Queen' - which we must now call Veilchenkönigin' - is a short aster which flowers by September. These violet and blue daisies are the perfect partners for yellow daisies and they will create autumn splendour in your garden, just when the autumn light is making the garden sparkle like a jewel.