When combining colours, consider the whole plant, says VAL BOURNE

I regularly visit Banbury market on Saturday mornings to buy plants from a Lincolnshire grower with a pitch near the bus station. Four or five well-grown plants for a fiver is a bargain. But I constantly find myself wanting to intervene when I see someone pick out five argyranthemum daisies in different colours. They are happy to use a pink, a yellow, a white, a red and an orange. But it would be so much better if they had five of one colour and drifted them through a border. I never say anything though, because my father's philosophy was each to his own' and so it should be.

But a trip to Broughton Castle near Banbury would teach anyone the wisdom of colour co-ordination. The long battlement borders were planted after advice dispensed by the American designer Lanning Roper in 1970, I believe. He used blue, white and yellow in one, and pink, purple and white in another and both borders were designed to spill and flow. The colour themes have been adhered to for 40 years and excellent teas can be had too!

But colour co-ordination needn't be as strict as you think. Flower arrangers put together a vase instinctively. They don't just go by flower colour alone. They look at the stems, buds, foliage and the flower detail and you can see them blending crimson flowers with bright blue saucers veined in red, or putting a pink flower with a brown middle next to orange and making it look right. It's all in the detail. Even the colour of the stamens matters and applying their rules to the border will also work especially if you remember that foliage, stem and bud are more vital than flower.

The RHS Hampton Court Palace Flower Show display, pictured, is a masterclass in blending plants well. Rosy Hardy (of Hardy's Cottage Garden Plants near Whitchurch in Hampshire) manages to combine the drooping pink petals of Echinacea pallida with a yellow tagetes and it works. The dark egg-yolk middle of the tagetes helps. She picks up the deep-pink cone of the daisy with dark alstroemerias, phloxes and bright-pink lavatera with just a touch of fresh white. Plenty of varied, bright-green foliage holds it all together. But perhaps what makes it work so well are the purplish stems.

I've just come back from visiting Dorset and Wiltshire gardens and I noticed how well the light-green buds on the flat heads of ice plants (forms of Sedum spectabile) show off vibrant colours like deep-red Crocosmia Lucifer' and purple salvias. I'd virtually abandoned these green-leaved butterfly magnets, which flower in September, for glamorous dark-leaved sedums like Purple Emperor'. But now I see their value and I've just surrounded a cream and green variegated Notcutt's pampas grass Cortaderia selloana Silver Feather' (one that shone at the recent RHS trial) with several ice plants to create a cool swathe of light summery green.

Similarly blue is a border stunner particularly in evening light. My orange heleniums shine brightly next to Agastache Blue Fortune'. It's just a pity that my tall apricot-orange, dark-leaved dahlia David Howard' has turned out be a lipstick-pink instead. Even flower arrangers would have trouble making that combination work.