Snapdragons (Antirrhinum majus) are colorful spike-like short-lived perennials often grown as annuals.    We have had them growing in our gardens, but we have only bought seed once, long ago.    They readily reseed or gardeners can easily collect seed at the end of the season.   We find them useful as a fill-in plant, especially on borders,  and we usually just scatter seed in late fall or early spring, possibly scuffling them into the soil.   Snapdragons have many colors and we sometimes see new combinations from the self-seeded ancestors.  

Although they are a cool-season bloomer, we find they fare well in full sun and in almost any soil.   Deadheading helps to encourage more blooms and excessive reseeding.   We cut them down at the end of fall to remove the stalks, but we also collect seeds and disperse them in good spots for the following season.

Snapdragons are one of the most reliable and rewarding flowers in the garden.