Dating from the early 17th-century with later additions, the main house is home to Dutch-born architect France Smoor and his wife Clare, who have lived here for 30 years. During this time they developed the formal walled garden beside the house and created water and woodland gardens, planted with drifts of snowdrops.
"When we came here there was almost no garden," says Clare. "Unusually for a Scottish walled garden this one is attached to the house. But it had just one herbaceous border, which divided the garden in two. We intended to work on the garden slowly but to our surprise we found that the project gained momentum in leaps and bounds."
Early on they laid out a formal box parterre in the courtyard in front of the house. Consisting of a pattern of eight interlinked circles, punctuated for height with columns of yew, the parterre boasts herbaceous plants in summer but in winter its clear edges are often outlined in frost or snow. The classic box theme is echoed in the pair of pyramids that flank the door and was later extended to outline beds in the half-acre walled garden. Here, among walls covered with rambling roses and clematis and planted with the graceful spring snowflake, Leucojum vernum, sits an octagonal summerhouse with a porch extended on iron pillars.
Designed by France, this Millennium project was made entirely from recycled materials.
"My husband loves a project," says Clare, "and when I needed somewhere near at hand to keep tools, he designed this multi-purpose garden shed. The iron columns were from a demolished steading in Fife and the doors came from a hospital. The metal balls on the weather vane were recycled from old-fashioned copper ballcocks."
The water garden, which lies north of the house, came into being suddenly and unexpectedly in May 2000. Clare explains: "We had hired a digger to do some agricultural work for four days. When the driver finished early he said he had half a day left and was there anything else we wanted him to do." On the spur of the moment the couple decided to excavate the boggy ground near the burn and create a pond.
Seeing the water undulating quietly round a central island planted with shrubs and small trees, it is hard to believe this is the result of an afternoon's work. Now reached by a series of grass paths and set with benches, the water is lined with reeds and grasses. "At the outset I intended to plant the island with herbaceous plants," says Irish-born Clare, who has always loved gardening. "But I soon found the island was too wet and I am now turning to shrubs."
Bulbs proved easier to establish and, in spring, snowdrops are succeeded by daffodils, bluebells, primroses and ribbons of orange, pink and red candelabra primula that have spread from an original purchase of six plants from nearby Cortachy.
A magnet for wildlife, including owls, squirrels, deer, kingfishers, ducks and plenty of supporting insects, the water garden is also furnished with benches.
The water garden is given shape and architectural structure by the recent restoration of an arch that frames the bridge over the farm track on the garden boundary. Reconstructed by local members of the Dry Stone Walling Association, it complements a stone seat that the association built last year. An old stone wash-house with a slate roof adds interest and a sense of perspective to the water garden.
The next major step forward took place nearly five years ago, when the doyenne of snowdrop gardens, Catherine Erskine at Cambo, added Gagie to the list of gardens open in the area for snowdrops.
Gagie already had extensive plantations of late snowdrop, but Clare immediately felt more early ones were needed and began splitting up and replanting snowdrops round the perimeter path, allowing carpets and drifts to extend back in the woods.
"There are now drifts of snowdrops on either side of the mile-long grass path that winds through the den and round the perimeter of the policies."
Here, through the shelterbelt of mature beech, oak and sycamore, winter days are enlivened with bright white pools of bulbs, some early, others late. You might also catch a glimpse of the couple's flock of Jacob's sheep.
Reflecting on the fact that there are plenty of benches and sitting places in sunny spots, Clare says that she doesn't have much time to hang around as she manages the garden more or less alone. "It takes five hours just to mow the lawns and paths with a ride-on mower," she says.
But creating the snowdrop garden has been a lot of fun and has made her realise how many lovely sunny days there are when you can be out in the garden in winter. "Nowadays I'm outside much more in the winter, splitting up clumps of snowdrops and spreading them around on both sides of the path." The trick is to find a sheltered spot in which to work.
• Gagie House, Gagie Duntrune, near Dundee DD4 0PR, is open for snowdrops from mid-February and remains open until the end of May for spring flowers. Beside the informal car park visitors can make themselves a cup of tea or coffee in the rustic kitchen.
This article was first published in Scotland on Sunday on 24 January, 2010