Quote Originally Posted by Matty
Can you destroy or knock down ladders?
Yes but it takes awhile and seems to be restricted to one ladder at a time (I'm going from memory here, I only bothered to do it once, a while ago).

I've also managed to torch enemy siege towers right at my ramparts, just as they'd completely filled up with all the enemy's best shock troop units. It was a real turning point in the battle but up until that point my focus was directed elsewhere, so I'm not sure if it was my wall archers or towers that did the deed for me.