Fractal, destroyed, ivy buildings.

So hey there,

So I’ve been working in blender for some time now, and i came to a point at the game where i need to have destroyed buildings(city) with crumbled stones, ivy on the buildings and rotten(Can be material anyway).

But i’m genuinely stuck on how to make such things, Broken buildings, i got 0 clue except subdivide and delete out stones manually but that doesn’t really seem to look good.
Second part is how to create flora on those buildings, like ivy growing, grasscracks, etc etc.

However, i know of IvyGen, but that’s too high poly for the game.
A good example is Crysis 3 buildings. Like these:

Could someone give me a workflow or a link to a place where i can find this information, as i’ve been looking myself but found not a lot of useful things.

Kind regards,

Key is to mix low poly with texture. Blend them to make them look real and complex. There are many images out there on the web. Look through them and borrow ideas. Key word, try, “City ruins in 3D mesh”.