Plants that normally produce only foliage the first year, then flower, set seed, and die in the second growing season. (Some of these may live and flower an additional year or two, particularly if you remove the flowering stalks before the seeds form.)
I am passionate about collecting and growing seeds. In the links below, you can find out more about why I started my own one-person seed company and how it works. The library page is a collection of articles I’ve written on seed-related topics.