Whether you call it an herb or a spice, saffron is made from the dried stigmas of one fall-blooming crocus species. This precious herb can be worth thousands of dollars per pound. Grow your own crop for significant savings in making your own paella. Plant this crocus in early fall; the corms will bloom 6-8 weeks later if the bulbs are planted 3-4 inches deep and about 2 inches apart. Saffron grows best in full sun in well-drained soil.