A captivating country garden grown from a few acres of farmland

Before you even reach this Herefordshire garden, you are momentarily but pleasantly distracted by a rather handsome belvedere, romantically reflected in a small lake, and designed by the architect Craig Hamilton to celebrate the millennium. Then what arrests you is the ethereal landscape. Even in high summer, a dreamy, low-lying mist rolls along this hidden valley and clings to the surrounding hills like spun gossamer. The Green perches on one side of a gentle hill, overlooking valley, river and wooded hills beyond.

Luckily, no one had realised how wonderful the derelict, sheep-inhabited farmhouse on the family estate could be until Patrick and Lorna Vaughan discovered it in 1981 and moved in with their five children. They immediately began extending the farmhouse, restoring picturesque old barns and dilapidated outhouses. Then, from nothing more than a series of small yards and a few acres of rough farmland, Lorna set about making a garden.

She was not sure exactly what she wanted, apart from walls and romantic roses, based on a lingering vision of the Gardens of Ninfa in Italy, and some hedges for structure. 'There's nothing more beautiful than hedges on a frosty winter's day,' she says. She decided not to enlist the help of a designer, but admits, 'Occasionally, I yearned for someone to come sweeping in and do everything perfectly.' Apart from a line of broken old poplars, there were no trees, so Lorna began by planting acers and sorbuses in groups of three, together with a now stately walnut.

Next came the layout, starting from around the house and working outwards. Lorna may have eschewed professional design help, but gardening expertise and designer conceits abound in this ebulliently planted five-acre garden: terraces tumble perfectly into the valley mist; and elegant iron gates, carefully sited trees and oversize tubs lead effortlessly towards spectacular 'borrowed' landscape.

At the back of the house, farm buildings frame an almost Mediterranean courtyard. Warm and sheltered - often seriously hot as it faces south - it brims with pink and white valerian, silver stachys and huge clumps of Crambe cordifolia. There are roses in abundance - Rosa californica 'Plena', 'Buff Beauty' and 'Eden'. The courtyard serves a dual purpose: in summer for sitting out (complete with a pizza oven) and in winter as shelter for citrus trees and other delicate plants.

Close to the house, a set of wide semi-circular steps, perfect for sitting on, leads to a bold box parterre, designed by Lorna and featuring a circular pond with a central wheel motif. 'Everything around here is to do with cider making; there are bits of cider press and old millstones everywhere and the cartwheel was inspired by that.' Lorna likes to fill the house year round with flowers, so below the parterre there is a small potager garden. 'Home-grown produce is always so much nicer,' she says. Along the length of the lowest terrace is a splendid blue and white border filled with nepeta, euphorbia, salvias, nicotiana and the palest verbascum.

In 2009, Lorna decided that she needed another pair of hands to help with her expanding garden and the arrival of Anna Stankiewicz put a renewed spring in her horticultural step. 'I loved the garden, but after 25 years I was playing it safe,' says Lorna. Anna had wanted to work in horticulture for as long as she could remember. She came to The Green from her native Poland, armed with a degree in commercial horticulture via eight years at Wisley, working under Jim Gardiner, and an 18-month stint at Jekka McVicar's Bristol herb farm.

Anna fell in love with Lorna's garden at first sight: 'Mrs Vaughan had laid down these wonderful bones already, so all I had to do was concentrate on the planting,' says Anna. The two women agree on a planting style, more or less, described by Lorna as 'immaculate but not too tidy', and by Anna as 'controlled chaos'. They share a strong gardening ethos: place plants where they will be happy; embrace self seeding; and, above all, be adaptable. 'If things have gone full circle or you're plain bored, never be afraid to replace and renew,' says Lorna. 'We'll try anything.' They are currently extending the planting season to bring year-round interest to the garden, and experimenting more with colour.

Wildflower banks and meadows are an ambitious new project. Initially difficult to establish in the over-rich farmyard soil, the grass in the wildflower areas has had to be cut and raked up to four times a season for the flowers to flourish, but persistence has paid off. Last year, the first orchid appeared amid a tapestry of oxeye daisies, mallows, bugle, wild geranium, yellow rattle, agrimony and campion.

Then there are the bees - Anna's great passion. They live in the orchard at the bottom of the terraces, surrounded by winter-flowering mahonia, honeysuckle and hamamelis. When foraging, bees react to temperature and not day length; fooled by a balmy day in winter, they will emerge from their hive but need to feed close by if they are to return. 'Bees are extremely addictive, I've become obsessed,' Anna confesses.

'This is as much Anna's garden now as it is mine. It's the two of us and the bees,' says Lorna, as they head off into their creatively chaotic but utterly enchanting garden.

The garden of The Green is open for small group visits by appointment. Call 07813-964362 for details