THE LAST TIME Deeda Blair covered her garden dining room walls with fabric was when the walls weren't finished. Deeda and her husband, William McCormick Blair Jr. (then head of the Kennedy Center) had to give a large dinner to mark the center's opening. The walls are painted now, but for a dinner tomorrow night honoring designer Sybil Connolly, Deeda Blair has transplanted Connolly's "Flowers from an Irish garden" onto her garden dining room walls and tables.

Deeda Blair said she and Sybil Connolly "became friends over flowers and gardens. We've given each other cuttings." She saw the sketches for the new fabrics in New York a year ago, and determined to use them. For her dinner, Blair will wear a Connolly pale lavender, pleated linen skirt.

Deeda Blair is well known as one of the two or three most elegant women in Washington. With her husband and their son, William McCormick Blair III, Deeda Blair entertains Washington's political and cultural stars in grand style at the Blairs' Foxhall Road mansion.

The house is red brick with a softening wash of white (though Blair likes to recall the cab driver who said, "I see you're like me, you don't have enough money to have your house painted.") The interior was decorated by Billy Baldwin. Chinese screens and ceramic jars and other oriental objects, some from the time Blair was ambassador to the Philippines, stand against antique white walls.

We talked over curried chicken and Deeda Blair's homemade chutney. The tablecloth was made of Connolly's pansy print, a good choice in the Blairs' formal dining room with its pale green, glazed walls. The table was covered with a flounced cloth decorated with pale yellow and lilac pansies on a creamy white background with touches of irish green. For lunch, Deeda Blair used as a centerpiece a marvelous papier-mache cabbage, much like the ceramic one Connolly uses in her dining room in her Georgian house.

The Blairs are welcoming Connolly tomorrow with a dinner for 20 friends. The Irish ambassador is entertaining Connolly the following night.

For the dinner, Deeda Blair has redecorated their dining rooms to celebrate the occasion. In the lower level garden dining room, she has covered the walls (and the windows and doors) with 65 yards of a Torrands-Textile, a red fuschia design on beige with a stylized bamboo trellis border. The pattern is similar to the fuschia pattern on Connollly's own dining room walls. In the Blairs' house, the fabric is pulled tight and stapled to the wall, top, bottom and along the smooth seams. Because this is a not-forever installation, the doors and windows are covered as well, without interruption. Jane Wilner, owner of Fabrications, did the stapling.

For the Connolly dinner, the tables for six will be covered with tablecloths, with matching napkins, made by Fabrications from Connolly's marblized fabric. "We don't have a proper wood table, so we always have to cover them up. I have the cloths Scotchguarded before we use them so they stay looking nice."

Pots of herbs will be centerpieces. The tableware has bamboo handles ("to save on polishing," said Deeda Blair). The plates are lacquered brown octagonals from a pottery in the south of France.

The floor here is brick, painted with white deck paint every year. Large trees grow in handsome baskets. The chairs are the ubiquitous turn-of-the-century faux bamboo ballroom chairs, painted white.

For cocktail napkins, Deeda Blair uses remnants of the Connolly fabrics, pinked, not hemmed, an economical way to give everybody a substantial way to tidy up after the canapes.

"I love the fabrics," said Deeda Blair, "because it seemed to me they can be used in a very individual, personal way."