quinne

Generally snapdragons are to heavy with blooms. either support them (THIN sticks if anything) or let them kinda fall over as they are wont to do. It helps to plant them close together sometimes so they can support each other.

Hit the post too soon...

Most however do not LIKE to be planted too close together.

If they have too much shade, that will make them floppy too.

use a good fertilizer, slow release... or feed them to strengthen sometimes just before flowering.

And as I said before some steaks will help.