Saffron crocus (Crocus sativus) is highly prized for the scarlet-colored stigmas (parts where pollen germinates) in the center of its lavender flowers. When dried, these threadlike stigmas are commonly known as saffron, which, at $171 to $357 per ounce, is the world's most expensive spice.

Why so costly? It takes around 4,000 hand-harvested stigmas to yield 1 ounce of saffron. But the corms (bulblike organs) cost only about 50 cents apiece, and they don't need chilling like spring-blooming crocus. For flowers in late September or October, plant them right after you buy them. Plant corms 3 to 4 inches deep and 6 inches apart in rich, well-drained soil in an area that gets full sun and no summer water. When a flower is fully open, its three stigmas are ready to harvest. Dry them on a paper napkin for 1 1/2 to 2 days until almost crumbly; store in a sealed jar in a cool, dry place.

ONE SOURCE: Brent and Becky's Bulbs (877/661-2852).