This gardener's mecca is on an unassuming stretch on Bayshore Boulevard, surrounded by dull warehouses and traffic rushing toward highway onramps. But step through the gate and you're in a deep green oasis, a quiet place where at least four cats prowl through the foliage and the chipper motto is "We Sell Happiness!" The knowledgeable staff members pride themselves on expertise with San Francisco's "microclimates," as delineated by the authoritative Western Garden Book, and they recommend plants accordingly. For the sunny Mission: Plant tomatoes, sunflowers, and citrus trees. (Ever heard of a limequat tree? They've got 'em.) For the foggier side of town: Embrace ferns. If your garden is within range of the ocean spray, check out the sea lavender, daisies, and Mexican feather grass. Wandering through Flowercraft with a little red wagon in tow is a thoroughly pleasant experience, and enough to get anyone's green thumb itching.