WHEN designer Sybil Connolly takes a plane back to Dublin, she looks for Mother Nature herself with plant cuttings sticking out of shopping bags, tucked under her arms, creeping out of her pocketbook, secreted under the handmade lingerie in her suitcase. Some have accused her of smuggling plants through persnickity Irish border agricultural inspectors, but she roundly denies it.

In Dublin, in her 1952 vintage Birstol limousine (for which she has refused $250,000) she takes all her cuttings to the Irish botanical gardens. Their experts coddle and care for them, and then when the plants are at the peak of bloom, Sybil Connolly takes them home to show them off in her Merrion Square mansion, across from the House of Parliment. So far, no one rails about taxpayers' money being used to take care of citizen Connolly's plants, but then she is credited as having given the botanical gardens a great number of their rarest specimens.

Anyway, Connolly is known as one with great powers of persuasion. She talked the Dublin government into letting her open a fashion boutique and couturier salons in her landmark five-story 18th-century Georgian mansion, the only commercial establishment so permitted.

Connolly, well-known for more than 30 years as a dress designer, was in the United States for the first showing of her new venture, decorative designs for interiors made by some 20 American manufacturers, introduced locally by Woodward & Lothrop.

The Connolly collection is called "Flowers from an Irish Garden Collection," a name as old-fashioned as a mixed flower bed. The primroses, fuchsias, roses, violas and poppies as well as faux marble, patchwork and friezework patterns have been transplanted to upholstered furniture, ceramics, china and glassware, bedliners, table covers ad closet accessories. The flowers are suggested by several sources: old botanical texts, especially Ehret, an early 18th-century artist; spring visits to Burran, a hidden Irish glen; and close observation of her own garden. The fabric sells for $8089 a yard.

At her Dublin mansion, flowers bloom not only in and on the trellised boxes and walls, and curving borders, but in ceramic pots, on rare Irish Delft plates, or Chinese Export porcelain, on bedroom walls, on sofas, comforters, curtains, plates, table coverings, pillows and plaques.

Connolly is a tall, handsome woman with great presence. You couldn't imagine her wearing small patterns, but her own dress designs in solid-color linens suit her very well. She has brown hair streaked with silver brushed in waves framing a fair Irish complexion. Connolly is the sort of woman you expect to wear pearl necklaces and earrings, and she does. She speaks with a voice once described as "Irish cream."

A few years ago, she might have been called, with a shake of the head, "the last of the remantics." For several decades, (except among well-bred people with old family homes and those who longed for the days of yore) flower designs were considered too flossy, to delicate, too feminine, too too much. But now, Connolly's one of the first of the '80s wave of romantic interior designers -- Ireland's answer to the Welsh Laura Ashley. (Through Connolly, Ashley and Mary Quant, all dress designers, were originally Welsh.) She has decorated many well-known houses and stud farms including the Aga Kahn's in Ireland and a few in the United States.

Flowers are a part of a whole wave of romanticism sweeping design today. The rustic country look, the artifacts of the post-modernists, the nostalgia of the oak drug store furniture reproductions, are evidence of a longing for the far away and long ago. The feeling is much like the pre-Raphaelian period in Britain in the middle of the last century. In out time, flowers began to spring up first in clothing, in the romantic milkmaid look, fostered by Laura Ashley. But now, the seeds of romanticism have flowered in home furnishings.

"With wars and rumors of wars threatening on every newscast, people like to escape to rooms that are pretty, that call up a feeling of gentleness, of innocence, of bucolic charms, of peace with nature," Connolly said the other day, over lunch in Deeda and William McCormick Blair's elegant Foxhall Road mansion.

Her first decorative design, "Angouleme," of chintz and wallpaper, was first produced in Britain and is distributed here by Brunschwig of New York. Connolly is using Angouleme fabric in the American embassy in Dublin for a suite of rooms, the main bedroom and sitting room, decorated with Ambassador Waller Curley's Chinese paintings.

"The motif was suggested by china made in the 18th century for the Duke of Angouleme," Connolly said. "I inherited 54 place settings from my aunt. She also left me her early 18th-century Irish silver and started my antique and modern Irish silver collection. Angouleme is white with sprigs of blue and green Veronica flowers -- my middle name is Veronica, so it's fated that I should like it.

"When I went to see Monticello, I saw that Jefferson too had Angouleme.

I'm a great Jefferson fan, I collect books and books about Jefferson, so I wasn't surprised we shared our taste for Angouleme. I've alwaystold everyone that I haven't married because I was hopelessly in love with Jefferson."

Connolly also collects rare Irish deelftware, Waterford and Simon Pearce glass. She has worked to revive traditional Irish handskills including chrochet, drawn threat work, embroidery and lace, handwoven woolens, the black shawls of Country Mayo and green basketwork.

Connolly grew up in the 17th-century house in Wales. "Our family arms were bestowed by Richard the Lionhearted. The lion rampart is chained, showing our family fought in the Crusades." At 15, she moved to Ireland.

In 1940, at 22, Connolly became Ireland's first custom dress designer in the fashion house of Richard Alan, after an apprenticeship with Bradley's, who made clothes for the royal family.

She became an independent couturier 10 years later. Jacqueline Kennedy Onassis wore a Connolly pleated linen dress for her White House portrait. Connolly still does not make a ready-to-wear line. Her dresses cost up to $2,000.

Twenty-three years ago she was prosperous enought to buy one of the great houses on Dublin's most magnificent address, Marrion Square, across the street from the Houses of Parliament and the Irish museum. She was one of the first along with Desmond Guiness, to call attention to the great Georgian houses of Ireland and work to restore and preserve them.

Her ideas of preservation are functional. She uses the ground floor of her mansion as a fashion boutique, the street floor for her fashion workrooms, and the first floor (the piano nobile) as her fashion salon. The top two floors are her duplex apartment.

When Connolly has grand parties, such as her Christmas Eve party, she uses the magnificent salons, covered in 1000 yards of finest blue-gray pleated linen, with green Irish carpets and monumental carved furniture, including soft poufs.

"I remember one year," said Lambert, "she had the choir, cherubic-looking boys from a nearby church to sing. The were given ice cream and cookies in an anteroom after the performance. After everyone left, Sybil went to turn on the security system -- and found the little angels had pulled all the alarm wires out."

Connolly's own quarters are more modest.

A spiral staircase leads upstairs in her quarters, with wallpaper with a drapery design. The other wall is mirrored to make the illusion of a double stairway.

Her dining room seats only about 10, but does so in grandeur. Her young butler serves with considerable style. Her sister, Judy, is a famous cook. The food is presented on some of the museum-quality china with elaborate centerpieces, silver columnar candles and silver beakers for water.

The dining table is a black lacquered Irish piece, trimmed with gold. The mantlepiece is marble with an appropriate neoclassical carving. A painting of roses hangs above the fireplace. The wallpaper is panels of fuschias, the design which suggested the fuschia textile being marketed here. The whole scene is reflected in a large console mirror.

In her drawing room, she had priceless plates displayed over her fireplace, including the Jesuit plates, made in China for the Catholic missionaries. Connolly found them at an antique store for a pound ($2 or so). They're worth about $1,000 each now. She has a number of Chinoisere pieces of furniture, black lacquer with painted designs. Most of the furniture is overstuffed, comfortable with pillows in flower fabrics, and, of course, Chinese cachepots with flowers everywhere.

In her library, she displays rare specimens of Irish delft, blue and white flowered china.

She also has restored a small mews (alley) house -- what would be called in Washington a carriage house, but what her friend, publicist Eleanor Lambert, calls a folly because Connolly has lavished so much money and attention on it. cLambert and Deeda Blair have stayed in the mews house when they visit Sybil Connolly.

The house is a miniature gem. The drawing room floor is in octagonal blocks of trompe l'oeil marble. In arched niches and display shelves, all ornamented with elaborate molding and fretwork, are more porcelain, baskets and shells, as well as the inevitable pots of flowers and flowered overstuffed seating. The dining room, comfortable for four, has rare blue and white china on the walls, and cane-backed chairs. French doors open to the garden.

The bathroom is decorated with trompe l'oeil paintings of shells and a marbelized frame for the tub.

Between the two buildings is a pleasant garden, with trellised walls for the clementis, a few architectural artifacts for ornaments, a winding walk with curving flower beds, Japanese maple and flowering fruit trees. The splendid arches of the mews house make a background for the garden, the major function of a folly.

Connolly, as Lambert notes, can be a formidable woman. "Her friends like to tell about the way she saved Lor and Lady Dunoughmore from the Ira. For years, Connolly has gone every week to take several dozen eggs to the Poor Claires, Sister of Charity. Shortly after the Dunoughmores were captured, Connolly delivered her eggs, and for the first time, went into the chapel and prayed. She asked for the deliverance of the Dunoughmores. The next day they were released. Connolly's friends were not surprised. CAPTION: Pictures 1 through 4, Textile designer Sybil Connolly has branched out into interiors. Her favored floral patterns are found throughout her Dublin home in the fuchsia dining room and the drawing room with its elaborate parquet floor. Connolly and Washingtonian Deeda Blair pause in Blair's dining room newly decorated with fabric designed by Connolly. By Harry Naltchayan -- The Washington Post; Picture 5, Inside "a miniature gem" in Dublin: The master bedroom of Sybil Connolly's 18-th century mews house -- what would be called in Washington a carriage house; Picture 6, Deeda Blair with a Sybil Connolly tablecloth; by Harry Nalchayan