moss is so lush-looking!
my neighbors' yard has a north facing front yard and almost every inch of it is covered in some form of moss: it's a great look to me!
of course, if you really wanted flowers or foliage, you would be out of luck because most plants couldn't deal with the lack of nutrients that most mosses thrive in. you could haul in compost and other soil amendments...fertilize and baby your precious transplants...soak in an epsom salts bath after all of your back-breaking labor
...or you could let mother nature create a beautiful tapestry for mr. toad.
grow your own moss on most anything porous by pureeing 1 part moss with 2 parts buttermilk or yogurt (forget the urine, ok?) and applying it to your desired future moss-y surface (and water to thin)... or make graffiti with it...takes about six weeks to appear.