Snapdragon Madame Butterfly Ivory

Last year I grew some Madame Butterfly Ivory snapdragons and was going to grow some more again this year. As annuals, I assumed that they would die back but they're still very much alive.



If I cut them back to the new stems, will they flower or will they only produce foliage? It'd make life a lot easier if I didn't have to sow any new seeds.

 

I've grown Black Prince for 4 to 5 years and just tidied them up each year and been rewarded with flowers. There's been a few casualties and this year I'm starting some more and will probably replace all the old ones.
Being lazy Sweet Williams and Wallflowers all do several years duty.

 

They should go on to flower ok, but they often get rust which is not good and more likely on overwintered plants.
Perhaps just grow a few more to add, just in case.