Saffron is a delicious and colorful seasoning that is used in breads, desserts, and main dishes in many parts of the world, especially in Iran. Without it, an Indian curry or Spanish paella just wouldn't be the same.
The bright red-orange threads you get when you buy saffron are actually the stigmas, or female portion, of the Saffron Crocus flowers. It takes hundreds of flowers to produce a commercially useful amount, which explains why saffron is so expensive.
For the home gardener, however, two dozen Saffron Crocus will supply enough of the precious spice in the first year for a few memorable dishes. Then, with each successive year, the corms will multiply, the size of the planting will increase, and you'll be able to harvest more of the spicy stigmas.
After 4 to 6 years, you should divide and replant the corms. Division prevents overcrowding, which can lead to a decrease in flowering.

In areas where Saffron Crocus are reliably hardy—USDA Zone 6 through 8 in the South, 6 through 9 in the West—you should plant the corms as soon as you receive them.
Saffron Crocus does best in full sun and well-drained soil that is moderately rich in organic matter. Ideally, the site should be relatively dry in summer, when the corms are dormant.
Plant the corms 4in deep and 4in apart. If gophers, mice, or voles are a problem in your garden, plant the corms in containers or line the bed with hardware cloth or a similar wire mesh. Flowers will appear the first fall after planting and last for about 3 weeks.
The grass-like leaves may emerge soon after the flowers or wait until the following spring. In either case, the leaves persist for 8-12 weeks, then wither and vanish, leaving no trace of the corms below until the flowers appear again in fall. It's not a bad idea to mark the area where you've planted your corms, so you don't inadvertently dig them up while planting something else.