Overwintering Your Snapdragons
Because snapdragons naturally thrive in cold conditions, it is possible to overwinter them in certain climates. If you live in a milder region, the whole plant may overwinter if you cover it with a substantial amount of mulch.
Overwintering can be handy if you don't want to plant new flowers or seeds next season. Dry conditions are also helpful if you want to overwinter snapdragons outdoors.
Sometimes, snapdragons will overwinter on their own if they are planted in a protected area. Again, this only works in milder regions that have warmer winters. This method seems to work especially well if you let the flowers seed late in the season.
How to Overwinter
Another method if you live in a very cold climate, is to plant the snapdragons in containers and keep them in an unheated area against the wall of your house. Place the plants under lights during the winter and control the humidity.
Although snapdragons are considered annuals, overwintering can help them survive into the next season. This may save you money on replanting while also making your life easier.