Hi, Well you can do both. It's really a matter of personal preference and, to me, the length of the border. To me, for example, if I have a border less than 20 feet I generally edge it with all one species, but if it's longer, I like to vary it, planting something different every three or four feet, but still only keeping just a couple of species. I don't recommend planting a wide range of species, just a couple that are complementary in height and color. If you like, check out the Garden Plans on this website. We have over 200 different plans you can look through.