DREAD AUGUST is with us still. And natives' fancies turn to thoughts of refreshing oases -- cool, shady retreats with clear streams or bubbling springs. We can't always provide running water, but we do know of some simple escapes that might fill the bill: a garden in a museum, restaurant or hidden away on a side street; a leafy hideaway in a luxury hotel; or the grounds of an estate or two.

AL FRESCO

WOODEND -- Surrounded by 40 acres of gardens and woods, this handsome mansion, owned by the Audubon Naturalist Society, is a manorial oasis.

Woodend's incarnations have been many. Once a hunting ground of the Algonquin Indians, the property became the fief of Charles Calvert, second Lord Baltimore, and his descendants. For 200 years thereafter, Woodend and its surrounding lanwere known as "Clean Drinking," in reference to its famous spring.

Under the aegis of the Audubon Society, the estate was renamed Woodend and the formal gardens became a wildlife sanctuary with a nature trail winding through fields, thickets and woods past a stream and a pond. The society offers nature and conservation programs throughout the year, including field trips, family programs and projects for inner-city schools. It's a refuge, for wildlife and people alike.

WOODEND -- 8940 Jones Mill Road, Chevy Chase. Grounds open dawn to dusk. Mansion: 9 to 5 Monday through Friday, Thursday until 7; starting October 6, it will be open Sundays noon to 5. 652-9188, 652-5964.

OLD ANGLER'S INN -- The Old Angler's Inn perches on a hill above the C&O Canal between Locks 12 and 13. Just 12 miles from Washington, this tree-shaded, rustic inn offers a cluster of tables near the requisite fountain. On a hot day, you can choose from two shady terraces on the hillside above. Or try the pavilion on the second terrace.

Old Angler's has a distinctly continental atmosphere. But don't be misled. It's in Colonial territory with a long history. Not far from the inn's garden, Captain John Smith made camp on his canoe trip up the Potomac in the summer of 1608. Young George Washington, as an officer in the French and Indian War, crossed the Potomac nearby on his way to the Battle of Fort Dusquesne. He also designed the locks of the canal nearby.

In 1860, the Old Angler's Inn opened to those traveling along the canal, as well as to the Maryland gentry living in the surrounding countryside. During the Civil War, both Southern and Northern units found respite at the inn. President Teddy Roosevelt hunted not far away and also fished in the Potomac at the foot of the hill below the inn.

Take your cue from Teddy. Explore the Potomac and the canal, and then retire to Old Angler's.

OLD ANGLER'S INN -- 10801 MacArthur Boulevard, Potomac. 299-9097. Closed Monday. Lunch: Tuesday through Friday noon to 2 p.m., Saturday and Sunday till 3. Dinner: Tuesday through Saturday 6 to 10:30, Sunday 5 to 9:30. Garden is open Saturday and Sunday noon until dark. Lounge open from 5 till midnight Tuesday through Sunday.

ST. THOMAS PARISH GARDEN -- Tucked away at 18th and Church streets NW, the church garden of St. Thomas Parish faces the ruined east wall of the church. The church, where Franklin Roosevelt worshiped for years, burned in 1970. The parish then established the garden for use by the community. And a community garden it is; only the village well is missing. The neighborhood, consisting mainly of residents of nearby high rise apartments, often gathers here.

A central greensward is bordered by brick walks. On either side a double row of linden trees offers lush shade. Flowers change with the season and include daffodils and tulips in the spring, asters and chrysanthemums in the fall. Surrounded by ivy, two brick terraces with platform benches proide space for reading or reflection.

Birds call over the sound of city traffic, expressing their delight in the garden. Trust their judgment.

St. THOMAS PARISH GARDEN -- 1772 Church Street NW. Open at all hours.

INDOOR WATERING HOLES

GARDEN TERRACE -- One of the best indoor oases west of Morocco, the Garden Terrace in the Four Seasons Hotel most resembles a Moghul pavilion, with tall pillars and light streaming in. It's very airy and very green, graced with a fountain, almost fifty trees and a jungle of plants from everywhere.

Among the unusual trees and plants are a majestic queen palm 26 feet high, a Kentia palm found only on Lord Home Island off Australia and a Pandanus tree from New Guinea. The pride of the Garden Terrace, though, is a cycas palm; fossils of this tree have been found together with dinosaur bones. Flowers, planted about or scattered in pots and baskets, change with the four seasons.

Noted for its afternoon tea, with scones and Devonshire cream, the Terrace also offers such delicacies as Beluga caviar and French sandwiches. And there are sherbets to cool the palate.

THE GARDEN TERRACE -- The Four Seasons Hotel, 2800 M Street NW. 342- 0444. Hours: Sunday to Thursday, 11 a.m. to midnight; Friday to Saturday 11 a.m. to 2:30 a.m.

GARDEN CAFE -- Cool marble everywhere. That's the Garden Cafe of the National Gallery of Art: 16-foot marble pillars, a magnificent marble fountain, marble-topped tables. Not a single painting or sculpture embellishes the marble mis en scene. Large plants form a green hedge around the cafe. This is not to suggest that the Garden Cafe is severe. The cafe's ambience is softened by six lofty weeping fig trees, green trellises on the walls, and, at the base of the fountain, plants that change with the season. In a niche, a three-foot-high urn holds a Chinese Ming tree; during other seasons you may find a towering arrangement of magnolia branches. Occasionally, lotus blossoms float in the fountain.

After a morning of absorbing art, have lunch or a glass of wine or coffee at the cafe. Afterward, wander through more galleries in the West Wing and you may happen upon one or the other of two magnificent garden courts, each with a fountain: conservatories in the Roman-Tuscan style.

GARDEN CAFE -- National Gallery of Art, Pennsylvania Avenue at Sixth Street NW. Monday through Saturday, 11 a.m. to 4:30 p.m. Sunday, noon to 6 p.m. 737-4215.

FARTHER AFIELD

MORVEN PARK -- If you've just got to cut loose of the city, set off for Morven Park, an elegant Greek Revival mansion just 40 minutes from Washington. Several miles east of Leesburg, Morven Park was once the country home of a Virginia governor, Westmoreland Davis, and is now a National Historic Trust property open to the public.

Morven Park's 1,200 acres hold many fascinations. Advance up the mile-long drive to the great house, wander on the lawns and through several formal boxwood gardens shaded by grand magnolia trees. There's a garden pool to linger beside as well.

Or follow the estate's nature trail. Then visit the carriage museum with more than 100 equipages, including phaetons, Irish jaunting carts and gigs. The museum offers one of the more interesting carriage collections this side of the Kremlin. Don't overlook the mansion, dominated by a Renaissance Great Hall. Beyond the hall is that Edwardian institution, the Trophy Room, complete with a white Bengal tiger skin.

Bring your own fixings and end your visit with a picnic on Morven Park's imposing picnic grounds. Tables are set on a greensward with boxwood borders and Greek statuary, making it all the more difficult to return to town and the 20th century.

MORVEN PARK -- Old Waterford Road, Leesburg, Virginia. The house, garden and museum are open to the public during weekends in May and daily from Memorial Day weekend through Labor Day from 10 a.m. to 5 p.m., Tuesday through Saturdays. Sunday, 1 to 5 p.m. Open weekends until October 7. Admission: Adults $3.50, children $1.75; special group rates, senior citizen discounts. 703/777-2414. To get there from the Beltway, go west on Route 7 through Leesburg; turn right on Morven Park Road, then left on Old Waterford Road, and right at entrance to the park.

WINDSOR HOUSE -- In Middleburg, in the midst of the Virginia hunt country, an imposing Federal edifice houses the Windsor House restaurant. Walk through the elegantly appointed dining rooms and out the back door and there a courtyard haven awaits you. Tall shade trees tower over tables set with flowers and candles. A splendid ash tree and a fine magnolia dominate the garden. Evergreens provide yet more greenery. To the west of the pebbled area, with its formally set tables, is a long greensward, and, of course, boxwood. On the lawn, informal tables and a chaise longue or two offer unhurried ease. Marble urns and tubs filled with impatiens add dashes of color.

At dusk the courtyard takes on a magical quality that carries through a candlelight dinner al fresco. The fare is English for the most part, with Virginia dishes and French cuisine served as well. Be certain to call for reservations, though, for the courtyard garden is often used for receptions and other festivities. It's in great demand on the days of horse shows, wine festivals and other events of the surrounding countryside.

Should you want to linger late, you can put up for the night at a nearby mansion or manor house that takes guests, such as Welbourne, just past Middleburg, or at Oakland Green, near Lincoln. Those country houses, with their imposing grounds, assure you of another green retreat.

WINDSOR HOUSE -- 2 West Washington Street, Middleburg. Restaurant: Monday through Saturday: lunch 11:30 a.m. to 2:30 p.m.; dinner 5 to 9:30 p.m. every day except Wednesday; closed Wednesday. Sunday brunch, 11 a.m. to 3 p.m.; dinner from 5 to 10. Unicorn Pub open 11:30 a.m. to 9:30 p.m.; closed Wednesday. 471-0471. To get there from the Beltway, take I-66 west, then U.S. 50 west to Middleburg; it's at the corner of 50 and Madison.

Caroline Lancaster last wrote for Weekend on country mansions and manor houses. Green Retreats That Refresh By Caroline Lancaster

DREAD AUGUST is with us still. And natives' fancies turn to thoughts of refreshing oases -- cool, shady retreats with clear streams or bubbling springs. We can't always provide running water, but we do know of some simple escapes that might fill the bill: a garden in a museum, restaurant or hidden away on a side street; a leafy hideaway in a luxury hotel; or the grounds of an estate or two.

AL FRESCO

WOODEND -- Surrounded by 40 acres of gardens and woods, this handsome mansion, owned by the Audubon Naturalist Society, is a manorial oasis.

Woodend's incarnations have been many. Once a hunting ground of the Algonquin Indians, the property became the fief of Charles Calvert, second Lord Baltimore, and his descendants. For 200 years thereafter, Woodend and its surrounding lanwere known as "Clean Drinking," in reference to its famous spring.

Under the aegis of the Audubon Society, the estate was renamed Woodend and the formal gardens became a wildlife sanctuary with a nature trail winding through fields, thickets and woods past a stream and a pond. The society offers nature and conservation programs throughout the year, including field trips, family programs and projects for inner-city schools. It's a refuge, for wildlife and people alike.

WOODEND -- 8940 Jones Mill Road, Chevy Chase. Grounds open dawn to dusk. Mansion: 9 to 5 Monday through Friday, Thursday until 7; starting October 6, it will be open Sundays noon to 5. 652-9188, 652-5964.

OLD ANGLER'S INN -- The Old Angler's Inn perches on a hill above the C&O Canal between Locks 12 and 13. Just 12 miles from Washington, this tree-shaded, rustic inn offers a cluster of tables near the requisite fountain. On a hot day, you can choose from two shady terraces on the hillside above. Or try the pavilion on the second terrace.

Old Angler's has a distinctly continental atmosphere. But don't be misled. It's in Colonial territory with a long history. Not far from the inn's garden, Captain John Smith made camp on his canoe trip up the Potomac in the summer of 1608. Young George Washington, as an officer in the French and Indian War, crossed the Potomac nearby on his way to the Battle of Fort Dusquesne. He also designed the locks of the canal nearby.

In 1860, the Old Angler's Inn opened to those traveling along the canal, as well as to the Maryland gentry living in the surrounding countryside. During the Civil War, both Southern and Northern units found respite at the inn. President Teddy Roosevelt hunted not far away and also fished in the Potomac at the foot of the hill below the inn.

Take your cue from Teddy. Explore the Potomac and the canal, and then retire to Old Angler's.

OLD ANGLER'S INN -- 10801 MacArthur Boulevard, Potomac. 299-9097. Closed Monday. Lunch: Tuesday through Friday noon to 2 p.m., Saturday and Sunday till 3. Dinner: Tuesday through Saturday 6 to 10:30, Sunday 5 to 9:30. Garden is open Saturday and Sunday noon until dark. Lounge open from 5 till midnight Tuesday through Sunday.

ST. THOMAS PARISH GARDEN -- Tucked away at 18th and Church streets NW, the church garden of St. Thomas Parish faces the ruined east wall of the church. The church, where Franklin Roosevelt worshiped for years, burned in 1970. The parish then established the garden for use by the community. And a community garden it is; only the village well is missing. The neighborhood, consisting mainly of residents of nearby high rise apartments, often gathers here.

A central greensward is bordered by brick walks. On either side a double row of linden trees offers lush shade. Flowers change with the season and include daffodils and tulips in the spring, asters and chrysanthemums in the fall. Surrounded by ivy, two brick terraces with platform benches proide space for reading or reflection.

Birds call over the sound of city traffic, expressing their delight in the garden. Trust their judgment.

St. THOMAS PARISH GARDEN -- 1772 Church Street NW. Open at all hours.

INDOOR WATERING HOLES

GARDEN TERRACE -- One of the best indoor oases west of Morocco, the Garden Terrace in the Four Seasons Hotel most resembles a Moghul pavilion, with tall pillars and light streaming in. It's very airy and very green, graced with a fountain, almost fifty trees and a jungle of plants from everywhere.

Among the unusual trees and plants are a majestic queen palm 26 feet high, a Kentia palm found only on Lord Home Island off Australia and a Pandanus tree from New Guinea. The pride of the Garden Terrace, though, is a cycas palm; fossils of this tree have been found together with dinosaur bones. Flowers, planted about or scattered in pots and baskets, change with the four seasons.

Noted for its afternoon tea, with scones and Devonshire cream, the Terrace also offers such delicacies as Beluga caviar and French sandwiches. And there are sherbets to cool the palate.

THE GARDEN TERRACE -- The Four Seasons Hotel, 2800 M Street NW. 342- 0444. Hours: Sunday to Thursday, 11 a.m. to midnight; Friday to Saturday 11 a.m. to 2:30 a.m.

GARDEN CAFE -- Cool marble everywhere. That's the Garden Cafe of the National Gallery of Art: 16-foot marble pillars, a magnificent marble fountain, marble-topped tables. Not a single painting or sculpture embellishes the marble mis en scene. Large plants form a green hedge around the cafe. This is not to suggest that the Garden Cafe is severe. The cafe's ambience is softened by six lofty weeping fig trees, green trellises on the walls, and, at the base of the fountain, plants that change with the season. In a niche, a three-foot-high urn holds a Chinese Ming tree; during other seasons you may find a towering arrangement of magnolia branches. Occasionally, lotus blossoms float in the fountain.

After a morning of absorbing art, have lunch or a glass of wine or coffee at the cafe. Afterward, wander through more galleries in the West Wing and you may happen upon one or the other of two magnificent garden courts, each with a fountain: conservatories in the Roman-Tuscan style.

GARDEN CAFE -- National Gallery of Art, Pennsylvania Avenue at Sixth Street NW. Monday through Saturday, 11 a.m. to 4:30 p.m. Sunday, noon to 6 p.m. 737-4215.

FARTHER AFIELD

MORVEN PARK -- If you've just got to cut loose of the city, set off for Morven Park, an elegant Greek Revival mansion just 40 minutes from Washington. Several miles east of Leesburg, Morven Park was once the country home of a Virginia governor, Westmoreland Davis, and is now a National Historic Trust property open to the public.

Morven Park's 1,200 acres hold many fascinations. Advance up the mile-long drive to the great house, wander on the lawns and through several formal boxwood gardens shaded by grand magnolia trees. There's a garden pool to linger beside as well.

Or follow the estate's nature trail. Then visit the carriage museum with more than 100 equipages, including phaetons, Irish jaunting carts and gigs. The museum offers one of the more interesting carriage collections this side of the Kremlin. Don't overlook the mansion, dominated by a Renaissance Great Hall. Beyond the hall is that Edwardian institution, the Trophy Room, complete with a white Bengal tiger skin.

Bring your own fixings and end your visit with a picnic on Morven Park's imposing picnic grounds. Tables are set on a greensward with boxwood borders and Greek statuary, making it all the more difficult to return to town and the 20th century.

MORVEN PARK -- Old Waterford Road, Leesburg, Virginia. The house, garden and museum are open to the public during weekends in May and daily from Memorial Day weekend through Labor Day from 10 a.m. to 5 p.m., Tuesday through Saturdays. Sunday, 1 to 5 p.m. Open weekends until October 7. Admission: Adults $3.50, children $1.75; special group rates, senior citizen discounts. 703/777-2414. To get there from the Beltway, go west on Route 7 through Leesburg; turn right on Morven Park Road, then left on Old Waterford Road, and right at entrance to the park.

WINDSOR HOUSE -- In Middleburg, in the midst of the Virginia hunt country, an imposing Federal edifice houses the Windsor House restaurant. Walk through the elegantly appointed dining rooms and out the back door and there a courtyard haven awaits you. Tall shade trees tower over tables set with flowers and candles. A splendid ash tree and a fine magnolia dominate the garden. Evergreens provide yet more greenery. To the west of the pebbled area, with its formally set tables, is a long greensward, and, of course, boxwood. On the lawn, informal tables and a chaise longue or two offer unhurried ease. Marble urns and tubs filled with impatiens add dashes of color.

At dusk the courtyard takes on a magical quality that carries through a candlelight dinner al fresco. The fare is English for the most part, with Virginia dishes and French cuisine served as well. Be certain to call for reservations, though, for the courtyard garden is often used for receptions and other festivities. It's in great demand on the days of horse shows, wine festivals and other events of the surrounding countryside.

Should you want to linger late, you can put up for the night at a nearby mansion or manor house that takes guests, such as Welbourne, just past Middleburg, or at Oakland Green, near Lincoln. Those country houses, with their imposing grounds, assure you of another green retreat.

WINDSOR HOUSE -- 2 West Washington Street, Middleburg. Restaurant: Monday through Saturday: lunch 11:30 a.m. to 2:30 p.m.; dinner 5 to 9:30 p.m. every day except Wednesday; closed Wednesday. Sunday brunch, 11 a.m. to 3 p.m.; dinner from 5 to 10. Unicorn Pub open 11:30 a.m. to 9:30 p.m.; closed Wednesday. 471-0471. To get there from the Beltway, take I-66 west, then U.S. 50 west to Middleburg; it's at the corner of 50 and Madison.