The physician can bury his mistakes," declared Frank Lloyd Wright, "but the architect can only advise his client to plant vines." And what more seductive spring cover-up have we got than wisteria? Overnight, its spindly creepers flush purple, exploding in a thousand blooms and flooding the air with a potent perfume. At a time when the rest of the garden is still asleep, wisteria lolls across rooftops and drapes the porch eaves in fluttering welcome. It's voluminous yet dainty, a hardy grower with old-fashioned grace. One of the world's most popular deciduous vines, it was introduced to the west from China in the early 19th century. In England, the Victorians went wild for it, calling it grape-flower as they coaxed it up stone walls and even twined it around trees. ("An old oak that has seen its best days would be a suitable support," suggested British garden writer William Robinson.) Locally, wisteria blooms from late March into May, leafing out when the flowers fall. In winter, the leaves turn gold and then drop, and the lavish vine becomes a twig--but not for long. In a couple of months, it blooms again, and the architect is back in business.