Those who think making gardens in the classical tradition is a lost art should meet the landscape architect Charles Stick. Better yet, they should take in his work at Mount Sharon, a private estate that this weekend will offer a rare glimpse into the rarified world of high design in the Colonial Revival style.

Stick is one of the few authentic classicists designing gardens today; in that regard he follows a lonely path made by his 20th-century predecessors in Virginia, Arthur Shurcliff in Colonial Williamsburg and Charles Gillette working in Richmond. “I design gardens for individuals across the country ,” he said. “No one ever sees them.”

Fortunately, Mount Sharon is owned by civic-minded preservationists Charlie and Mary Lou Seilheimer, who are opening the garden Sunday, Mother’s Day, to raise money for two charities.

“If people want to see it,” said Mary Lou Seilheimer, leading me through the rose garden, “here’s your big chance.”

Stick and the Seilheimers worked collaboratively to create the 10-acre garden. Even by Stick’s standards, it is a formal garden of rare scale, high design and wonderful vernacular craftsmanship.

If you go, you will find such elements as an octagonal terrace with a view northward to the Blue Ridge and a long and alluring central tunnel of boxwood that will take you to places that are cozy or grand and wholly unexpected.

In one garden room, the space is cozy and grand at the same time, with busts of Jefferson and Washington in vegetative niches, a central lead statue of Eros, and a paving of brick and flagstone of uncommon design and craft. The place is called the exedra, after gardens where the Ancients positioned statues of their worthies for contemplation and discussion. At Mount Sharon, the pedestals for the other two local boys made good, Madison and Monroe, are still in need of busts. (Harder to find than their presidential predecessors, says Mary Lou Seilheimer.)

Before reaching the exedra, though, the visitor finds an intimate knot garden, where a double parterre features patterns of clipped and intertwined ribbons of barberry (Crimson Pygmy) and box (Green Gem). A nearby flower garden features hydrangeas, camellias and a central bed of forget-me-knots now in full bloom.

Elsewhere, a long terrace contains a double border that peaks in summer but for now is just stirring and offers a balcony with a thrilling view of Mount Sharon’s large and majestic rose garden.

Many of the 100 or so roses will be coming into flower this weekend, including the climbers that drape a pair of pergolas of white cedar. The roses include the dependable soft pink New Dawn but also lovely heirloom varieties such as the creamy Mme. Alfred Carriere and the blush pink Zephirine Drouhin.

The pergolas, of white cedar stained a gray-green, are separated by the main path through the rose garden (classical gardens are all about axes and cross-axes). This is the spot, I think, to get a sense of the high design and craftsmanship, with the series of sinuous, molded-brick walls and the exquisite lead statue of Mercury.

Mary Lou Seilheimer and her husband, a founder of Sotheby’s International Realty, have an abiding interest in historic properties and preservation.

They moved to Mount Sharon in 1997 from Warrenton and then set about designing and building the garden with Stick in an active collaboration. Though a historic site, the house at Mount Sharon is a Georgian Revival built in the 1930s to replace a Second Empire house, and the garden consisted of some old trees, the central boxwood walk, a small amount of terracing and not much else. The new garden took three years to construct and was ready for the Seilheimers’ daughter’s wedding there in September 2003.

The garden is reminiscent of the Colonial Revival gardens developed in Virginia between the 1920s and 1950s but is large and complex by even those standards. “I walk through this garden and I feel I am in a different time and age,” said Stick, who last month visited Mount Sharon for the first time in two years.

There is a thriving interest and industry in restoring both Colonial and Colonial Revival gardens, but the creation of whole new American classical gardens is rare, not least because they take deep pockets to build and maintain.

The danger, of course, is that you may create an enormously expensive artifice — a garden as ersatz as its McMansion.

To create an architectural garden that works takes a great deal more than structure and pretty statuary.

“I had a professor, I remember him saying, ‘Everything that’s beautiful has been done before,’ ” said Stick, who studied landscape architecture at the University of Virginia. “It resonated with me. If things are true, they respond to the context that surrounds them.”

The proportions of the terraces are linked to those of the house, he said. The resulting garden rooms become “an exercise in establishing harmonies, through geometry, through the linkage of one space to another.”

More fundamentally, there is an awareness of the spirit of the place — designers call it the genius loci — that guides the elements of the garden. At Mount Sharon, this is tied up with the surrounding terrain, climate and history of the region.

This is perhaps why the most “magical” space for Stick is on the octagonal terrace with a clear view across two large ponds to the Blue Ridge. Both Mary Lou and Charlie Seilheimer like to look across parts of the garden and to lower terraces — she from the pergola looking down into the rose garden, he from the urn terrace enjoying its prospect.

I too like the urn terrace, whose floor of turf and walls of hedge bring the eye to the plump and ornate stone urn held like a Faberge egg in its space. But the power here is in the crafting of the void, the negative space around the urn. It brings home the idea that Mount Sharon is, at heart, about sculpting the air.

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The gardens at Mount Sharon are open Sunday from 10 a.m. to 5 p.m. The estate is on Route 600 (Mount Sharon Road) in Orange County, Va., about two miles north of Route 20. Tickets are $30 at the gate, and proceeds go to Preservation Virginia and the Boys & Girls Club of Orange.