Gardening: Haven on earth?

Barr Kazer bid most generously for me in The Independent's Christmas charity auction and recently, as the first blossom began to appear on the blackthorn and winter seemed to be in retreat, I went to Tring in Hertfordshire to give the Kazers what they'd paid for: a day's consultation on their garden, followed up by a detailed report. It turned out to be one of the trickiest visits I've made.

Why? Well it certainly had nothing to do with what professional garden designers (I'm not one) call "the clients". Barr and her husband Brian could not have been more hospitable. Nor was the garden itself particularly problematic, a front patch 12 metres wide and 18 metres long, the back the same width but slightly longer, so that the house sat comfortably in the middle of its plot. It was built in the Seventies, part of an estate developed in the modern style, with no boundaries between pavement and front gardens. The tricky thing was finding the right balance between the Kazers' vision of the garden as a sanctuary for wildlife and their desire that it should look beautiful at all times of the year.

The Kazers moved here from the North 13 years ago and spent a great deal of time in the first few years making the garden as attractive as possible to wildlife. The lawns, both front and back, were left to grow into haymeadows. They planted hedges of mixed natives – hawthorn, holly, blackthorn, briar rose – down their two larch-lap-fenced side boundaries. They dug a pond. They added plugs of scabious, knapweed, square-stemmed St John's wort to the grass to increase biodiversity. A haymeadow in the suburbs of Tring is a novelty, but the Kazers were pleased when neighbours stopped to look at their front lawn, waving with tall grasses. It became a symbol of all that they believed in and they hoped it was an idea that might be copied.

The meadows still give them great pleasure, but Barr felt the garden as a whole should be delivering more. It lacked interest between May and June, she said, and again between September and February. To attract and keep insects you need to provide a regular flow of nectar and by plugging the gaps she hoped they might make their plot more attractive to wildlife, as well as making it more interesting to look at and be in. Apart from the meadow, at its best in early summer, she thought the front garden was boring. They both liked their native hedges, but wanted ideas for underplanting the scruffy area underneath them. She'd tried to provide shelter and a potential nesting site for birds by planting a bulwark of lonicera, holly and cotoneaster at an angle to the right-hand boundary, but it looked odd and the birds hadn't taken to it.

She'd made a wish list with wildlife at the top of it. As far as possible they wanted to use native plants in their garden. Their soil is fast-draining chalk, but they hoped not to have to water. They were looking for that combination of privacy and sun that is so tricky to achieve in built-up areas. If you raise your boundary you risk creating shadows long enough to stretch over your entire plot. How much did the Kazers actually want to garden? I know what I'd have done with the plot, if it were mine, but that was not the point. I was there to try to help them towards their particular vision.

Was it attainable? Wildlife of all kinds – plants, insects and the birds that follow them depend on corridors of opportunity. If a whole chain of traffic and cat-free land linked the Kazers with the Chilterns that they can see from their back terrace, they'd have a better chance of attracting all the things they want to see on their plot. But it doesn't. Their particular way with lawns hasn't caught on in the neighbourhood, though they go on hoping, and I'm pretty sure Barr knows that her present dissatisfaction with the way things are has to do with the garden's lack of structure.

We started with the easy things first – underplanting for the hedges, for which I suggested Cyclamen hederifolium, masses of violets, purple, pink and white, primroses and epimediums, arums such as beautiful Arum italicum 'Pictum' with marbled leaves, bluebells and hart's tongue fern. Generally, I felt that the Kazers' garden could be much more profuse than it is, and that would attract a variety and profusion of wildlife.

I don't actually believe that if a garden is to attract wildlife, it must only be planted with native plants. According to Butterfly Conservation, the top 10 plants for butterflies are buddleia, sedum, lavender, aster, marjoram, aubrieta, valerian, scabious, bramble and French marigold, which suggests that they don't make a distinction between native and non-native, as long as the nectar keeps flowing.

There's an intrinsic interest in growing native plants of course, and the Kazers have made the best of their chalk soil by letting their lawns develop into wildflower meadows. The garden, though, would look better and be easier to maintain if they made clearer divisions between its different elements. I suggested they installed a board edging along by the hedges to give a clean line to the grass that buts on to them.

Then, they could mulch the hedges every autumn that would provide much-needed humus for the fast-draining soil. Brian had used coarse wood chips as a mulch, but these take a long time to break down and rob the soil of nitrogen as they do so. It's not so easy to underplant between woodchips as it would be if they used mushroom compost.

Barr said she felt happiest working in the smallish gravelled area next to the terrace at the back of the house. She liked seeing how the patch evolved, what seeded into it. Since there were some awkward small areas of grass next to it, I suggested they gravelled those as well, using perhaps a different grade of gravel, 10mm rather than 20mm. I'd broadcast seeds of annuals in it too: poppies, single marigolds, Californian poppies (Eschscholzia), cornflowers and love-in-a-mist, to add colour and interest close to the house. All germinate surprisingly well when scattered on gravel.

The structural things I suggested – such as replacing stepping stones in the grass with a proper path, providing a notional division across the garden with a pear screen, demolishing a redundant low wall by the terrace, and so on – will do most to improve the overall look of the Kazers' garden.

But it could also do with many more plants. We talked about a new bed in the front, planted with drought-resistant things that would provide the late summer interest they needed. I suggested a small new shrubbery, rich with autumn berries to replace the barren lonicera. I made lists: plants suitable for chalk soils, plants to peak in May and June, plants to peak from September to February and – the longest list of all – plants to attract wildlife. But will they find the equilibrium necessary to satisfy their needs? The Kazers have a dream and I don't want to be the person to spoil it.