If you put enough good soil to landscape rock,can you plant perennials

You should be able to http://www.basicsofgardening.com/getting-your-garden-soil-ready.html good luck!

If the soil lets the roots grow and water gets absorbed readily, I would guess YES! Have fun!

Yes that is fine.

Are you moving the rocks away before you plant? Or are you talking about leaving the stones and putting soil on top of the rocks?

Just make sure you put lots of soil on top so the roots have enough room to grow. I had trouble growing grass over an old farm driveway in our backyard in Texas. The builders left most of the gravel and just put some soil and sod on the yard. The gravel would heat up in the summer and kill the grass that was above it. Good luck on your new garden! I hope it turns out beautiful.