I've had this baby pink snapdragon for about 3 to 4 years and I've noticed that this growing season its growth is very slow and stunted. For example, last year the plant grew to 3 ft tall and now it's approximately 1 ft tall. I'm thinking I might have to divide the plant with a shovel or do something else. During the winter, I overwinter the plant by placing leaf mulch around it. I usually don't prune it until the upcoming spring. Should I prune it before the first frost and then mulch? How much should I prune it? Thanks for your help and suggestions.
These plants normally cannot be divided successfully and are normally propagated via seed or cuttings. Snapdragons are most often treated as annuals, though they are actually tender, short-lived perennials. It could be that your plant is reaching the end of its days, so you may want to save some seeds or take some cuttings from it to start again, just in case. As for pruning, once the blooms have faded, you can cut the plant back by one half to one third (save some cuttings).