Rising sun Herbs. 18745 Frederick Rd., Gaithersburg. Monday through Saturday, 10 a.m. to 5 p.m.; Sunday, noon to 4 p.m. 926-8940.

A riddle: What are, variously, used for repelling dogs, rabbits and insects; imparting flavor and aroma to food; soothing an ailing spleen; refreshing the air with fragrance; and ornamenting a garden or windowsill? The people at Rising Sun Herbs will tell you that there are herbs that really (or reputedly) do work in all these ways, and they'll give you a complimentary tour of their greenhouse and garden to make the point. With 44 varieties of organically grown herb plants for sale (80 cents to $3.75), along with a selection of herb seeds, herb books and herb potpourris, Rising Sun Herbs sees as its primary task educating people about the cultivation, uses and history of herbs. The staff's advice to plant buyers is made easy to remember on handy printed summary sheets, and they'll give you recipes to try using the herbs you buy. You'll also find hanging planters ($6.75 and $9.25), each consisting of several herbs that accent the flavor of certain dishes, such as eggs and cheese or spaghetti or salads. You can also buy bunches of fresh-cut herbs here through September. After you've been convinced of the merits of having your own herb garden, you can use their services as landscape gardeners to plan the type that's right for your needs.