Cooke's travels through Europe as a child are what inspired her and left a deep impression. Living in Williamsburg, Virginia, and exploring the grand formal plantings of Europe, she developed a love of garden design at a young age.

It wasn't until years later that Cooke put this passion into practice. In 1990, she moved to England with husband Chris; sons Graham, now 24, and Nicholas, 21; and daughter Caroline, 13. After visiting and reading about gardens for years, she enrolled in a one-year diploma course at The English Gardening School in London in 1999. "That course was tougher than my degree," she laughs.

All the hard work honed Cooke's love for English garden style and taught her the importance of genius loci. "Any good design must address the landscaped area as well as respond to the existing architecture, and for me, symmetry is the driver," she says. Preferring winter to summer and a green garden to a flower garden, she mastered a pared-down style that suited her first major English project well.

While the family home is on a famous central London garden square, for which she is the consulting designer, the Cookes wanted a country getaway. Despite her husband's initial skepticism, they bought Keeper's Cottage, an almost derelict Victorian cottage built in 1863 without running water. Tucked away in a rural Gloucestershire valley and formerly part of the Lypiatt Park estate, it is a secret, magical place. There is not a neighbor to be seen, just towering wooded hillsides, old stone walls, and, after Cooke undertook a major restoration, a dreamy, fairy-tale cottage.

Creating the garden was not all smooth sailing. "Although England has a wonderful climate for gardening, we are in a frost pocket here. I look back over my garden diaries in amazement and trepidation as every year is so different," says Cooke. "It's a bit like The Wind in the Willows, with moles and water voles. Deer eat my plants, and foxes and badgers abound."

The one-acre triangular site is awkward. The cottage sits tight in the top corner, and a stream, which used to feed vast Victorian fishponds below the house, divides the property in two. Cooke began by designing the large Yorkstone terrace -- the key outdoor living area -- and right outside the kitchen/dining room sits a boxwood-edged herb knot garden with pots of tall lilies for color.

Once the hardscape was planned, Cooke meticulously studied the land. Wanting the best from each season, she included a winter snowdrop display; swathes of naturalized daffodils and bulbs within the meadow grass, through which she mows paths; and an exotic bog garden. Edging the terrace are groups of black and white tulips, santolina, lavender, and allium. It was important to make sense of the wedge shape, so she plotted vistas through the rose-covered pergola to a four-sectioned rectangular potager, where she grows vegetables punctuated by dark purple dahlias. One's eye is led through a blurred boundary into the ancient oak and beech forest rising beyond.

A drystone wall runs close behind the house, and through it, the stream runs into the abandoned fishponds. "This area is the most difficult of all. I recently planted 30 Himalayan birch trees, which I hope will thrive in the damp," says Cooke. One of the most charming aspects of the garden is the lumpy old walls. She has sensibly left them alone to be colonized by indigenous alpine succulents.

The family spends weekends and holidays at Keeper's Cottage. "It is a perfect retreat from London," says Cooke, "a great place to work, entertain family and friends, and allow my Welsh terriers to run riot."