A LONG with a few sprigs of mint, sweet woodruff, asperula odorato, is among the first herbs to turn green each spring. As a ground cover it's popular with local gardeners because it spreads rapidly and thrives in moist, shady woodland settings.

And even if it had no culinary uses, it would be an attractive plant to have around. Slender square stems, from six to 12 inches high, are encircled by aromatic whorls of six to eight almond-shaped leaves. By May, clusters of tiny white flowers top the foliage. It's no wonder woodruff-flavored beverages have come to serve as a sign of the season.A

The plant's fresh, woodsy aroma and the tart, slightly lemon-flavored extract, or juices, set off the flavor of dry wines and some fruit juices. And the leaves can be steeped for 10 or 15 minutes in boiling water to make a tart, pungent tea.

Along with many other herb teas, woodruff has often been used as a folk medicine, or tonic, reputed to have healing qualities.

May wine, an alcoholic fruit punch, is a German tradition. The following recipe is made during an annual May festival held in Herman, Mo., a small, historic village founded by German immigrants in the 19th century on the banks of the Missouri River. MAY WINE (Makes 3 quarts) 1/2 cup sugar 10 sprigs freshly picked, washed sweet woodruff 2 quarts dry white wine, chilled 1 quart canned, unsweetened pineapple juice, chilled 1 cup fresh, washed, hulled strawberries 1/2 cup sugar, optional Sprigs of woodruff for garnish

Place the sugar and the woodruff in a punch bowl and crush the herb with a wooden spoon. Let sit for about an hour. Add the wine, pineapple juice and strawberries. Stir well. Taste. If necessary, add a little more sugar. Serve immediately in wine glasses garnished with additional sprigs of woodruff. ? FLAVORED SHERRY

Open a bottle of dry sherry the day before serving. Pick and wash 10 sprigs of woodruff, and force them through the opening one at a time, pouring off a little wine if necessary to accommodate the herbs. Replace the cork firmly in the bottle and let the herbs steep in the wine overnight or until ready to serve. Pour in wine glasses garnished with additional freshly picked, washed woodruff. A bottle of woodruff-flavored sherry makes a nice present to bring to a friend. MAI BOWLE (Makes 7 quarts) 20 sprigs freshly picked, washed sweet woodruff 1 quart good brandy 1 quart dry champagne 5 quarts dry white wine 2 trays ice cubes or a 1-quart block of ice 1 pint fresh, washed, hulled strawberries Sprigs of woodruff for garnish

Cover sweet woodruff with brandy and soak overnight. Strain, and place the brandy in a punch bowl. Add champagne and wine. Add ice, float strawberries and sweet woodruff on top. Serve immediately in wine glasses garnished with additional woodruff.