I have a west facing homemade planter in the shape of a semi circle with a radius of about 8'. It is raised about 2-3 feet. I used bricks to build the planter. I have day lilies, easter lilies and an assortment of other plants growing in it. I want to place cascading plants on the edges of it so that the brick wall is partially obscured. I would like something that looks good all year round, grows quickly (don't want to wait too long for it to fill out)and is not too invasive (although I can trim it back away from the flowers if need be.) Recommendations anyone?