We're going to be laying down flagstone in our front yard and half will be in the shade with the other half in mostly full sun. I'm a walker so I've been on the lookout to see what folks use in between the flagstone and - for the most part - it's grass however on a walk through the Venice Canals (Venice, CA), I saw this beautiful deep green mounded moss that looked glorious and rich in between the stone. Of course did I take a photo? Drats. I don't know what kind of moss it is. It definitely had an undulating form to it and the color was very green. Unfortunately the moss was in a shaded area so if I used this moss, all over, I'm assuming it would dry up in the sunny areas. Since the entire section of flagstone is one whole area (sort of shaped like an 'L'), if I use two different kinds of groundcover between the flagstone, what will happen? Will they stay separate or will one take over the other or ?