For some midwinter dreamers, spring means the budding chestnut trees along Parisian boulevards or the sudden appearance of baseball scores from the Florida Grapefruit League. Both are cheering images for me, but can they equal the vernal explosion of flowers in Charleston, S.C., a city of endless and unmatched gardens?
Charleston blooms in all seasons, but the coming of azaleas in mid-March is perhaps its most splendid moment. This is when the low-country heat begins to rise and residents of the wondrously preserved antebellum city come out to putter in their yards, which they call gardens and pronounce ''gyahdens.''
If there is an official arrival of spring, it's during the Festival of Houses from mid-March to mid-April when a number of historic residences and gardens are open for afternnon and candlelight tours (write Historic Charleston Foundation, 51 Meeting Street, 29401.) For most of the year the priceless blocks between Broad Street and The Battery can only be appreciated from the sidewalk, and the little gardens must be glimpsed through the filigree of wrought-iron fences. So the chance to break through the rather well-sealed society is enticing.
My only question, as I made a candlelight tour one fragrant March evening, concerned the whereabouts of the residents of the houses while we interlopers trooped in and out of their parlors. Were they out to dinner, or hiding upstairs? Then in the Cleland House, at 58 Tradd Street, I got a partial answer. As our guide described a portrait above the mantel, a little boy in a bathrobe rushed through the room and disappeared up the staircase like a fleeing ghost.