“They are very 'quite’,” we say firmly.  Another problem is that a few of the people we work for not only have no gardening knowledge, but also plan to employ a gardener with pool management and car driving skills, rather than with any horticultural background. We get around this by suggesting a brilliant trainer and troubleshooter who goes in perhaps once a fortnight to give the “gardener” a crash course in how to manage the place.  His greatest success was to turn a couple who had never gardened before into competent veg growers and mowers, who knew what to do in a simple border to keep it looking good all year and could train climbers beautifully – all in the space of six months. They ring Peter whenever they have a problem and that works a treat and is a huge relief to us.  What clients often fail to grasp is that the success of any garden is 40 per cent design and 60 per cent maintenance.  Fast facts for foolproof borders  We never have a standard scheme, but there are certain plants which it is hard not to include because they are so reliable. Modern naturalistic borders tend to be a post-midsummer feature. This does not suit clients who want a tidy look and all-year interest. Our own gardens are wild, labour-intensive and we get crazes for new plants all the time. We reckon to stake most things, and we like half-hardies, bulbs and self-seeders in mixed borders. However, all this can be a bit too complicated to be dependable, so we have to find a way of delivering the effect the client wants more simply.  The good thing about starting with a fairly foolproof scheme is that you gain the confidence of the client and, as their gardener becomes more skilled, you hope to go back and vary the palette. Ideally, the novice owner and gardener both get the plants bug and that is when the new garden starts to get interesting.  The way to deal with the all-year “no dirt” problem is with an underpinning of evergreen and plenty of early bulbs. Piet Oudolf taught us that structured shapes in a sea of naturalistic planting will anchor the whole scheme.  Because box has become so unreliable (thanks to blight), we like to use evergreens such as phillyrea, osmanthus, sarcococca and Skimmia x confusa 'Kew Green’, with yew for bigger beds. Useful small evergreens include daphnes, ferns, bergenias, euphorbias, Iberis sempervirens and hellebores, but we never dedicate more than 30 per cent of the bed to winter duty, to ensure room for summer effects.  Grasses are a help because they can look good if winters are not too wet. One very easy, and effective, scheme we came up with includes lavender 'Sawyers’ and the grass Molinia caerulea subsp. arundinacea 'Fontäne’.  In November and December it is hard to keep bare ground covered. Unfortunately most clients do not like the look of dead brown stems left for the birds. We plant Cyclamen coum under shrubs, where they will be shaded in summer, and from January these and snowdrops can keep the “dirt” half-decent.  Add scillas and Iris reticulata and the bed will look good through February and March; their dying leaves will disappear as other plants emerge. If a few get dug out, they can be topped up from time to time.  Bulbs are useful in new schemes as they fill in the gaps while other things grow. We like to use tulips in a naturalistic way because they are a source of instant colour for any scheme. Alliums and regale lilies can look showy in the first summer and, if the ground seems too bare in the early stages, we might also add biennials like honesty, sweet rocket and foxgloves.  Then there are the plants which look good even when not in flower. We include about 20 per cent of these – more if grasses are allowed. Iris pallida is a favourite because, unlike most irises, its blue-grey leaves look good for months.  Acanthus, especially the new white-flowered 'Rue Ledan’ is another standby in shade. Sea kale (Crambe maritima) has good foliage, as does agapanthus. Some clients ban red and orange, but Crocosmia 'Lucifer’ is useful if they don’t. Thalictrums are lovely and, on dry soils, the thistlelike eryngiums thrive. In silvery schemes the bold dianthus 'Bailey’s Anniversary’, 'Laced Monarch’ and 'Rose Joy’ are all good and when in flower they provide scent, which is important.  These are the plants with long flowering seasons; they make up about 30 per cent of a typical planting plan. Geranium 'Rozanne’ is irresistible. Valerian (Centranthus ruber) is unstoppable in red or white – never pink because it is too murky – but it does need deadheading. Aster x frikartii 'Mönch’ is good, but needs staking unless it gets the Chelsea chop. (With inexperienced gardeners we try to avoid using plants that need staking.) Japanese anemones in pink or white are hard to leave out and Phlox paniculata 'Blue Paradise’ is another favourite. We often use Daphne x transatlantica 'Eternal Fragrance’, as it has smart foliage and flowers all summer.  The mix varies, but it helps to set out a list of what flowers will be out in which season, so that you can see where the shortfalls are.  For showy flowers – the final 20 per cent – we add carefully chosen roses. Most clients ask for them (they also ask for catmint and alchemilla, but we tend to resist those, because they are overused). In hot places, where the brief is bold colours, we might suggest Rosa x odorata 'Mutabilis’. This is a single rose in shot flame and orange which is out for ages and has a freer habit than most. It needs no deadheading and rarely gets diseases. Another single, long-season rose we often plant is the new 'Kew Gardens’. More traditionally, 'Winchester Cathedral’ or 'Margaret Merril’ are good whites and 'Munstead Wood’ and 'Young Lycidas’ are rich purples. 'Gertrude Jekyll’ is a reliable pink with an old-fashioned shape.  Dahlias are invaluable with three months of flower but they do need staking and protecting in winter. For the cautious we might use 'Porcelain’ and the crimson single D. coccinea that seems almost hardy here. The bolder client might end up with 'Hillcrest Royal’, 'Grenadier’, 'Roxy’ or 'David Howard’.  Cyclamen, snowdrops, crocus, scilla, Iris reticulata  Tulips, lavender, euphorbia, alliums, honesty, sweet rocket, Iris pallida  Roses, lilies, thalictrum, sea kale, foxgloves, Geranium Rozanne  Roses, lavender and geranium will continue to flower. Dahlias, agapanthus, Japanese anemones, crocosmia, phlox, eryngium, Aster x frikartii 'Mönch’  Evergreen shrubs come into their own, such as phillyrea, osmanthus, sarcococca, skimmia, yew. Smaller evergreens include ferns, bergenias, euphorbias and hellebores. Dianthus stays blue-leaved all winter
Designer Mary Keen shares a plant list and a design strategy that   satisfies the wildest dreams of her most demanding clients.