We have a garden loaded with lilies, tulips, columbines and a few others. Starting with almost pure sand that we can't even grow grass in, but the weeds seem to do okay, we added 2 to 4 inches of well composted horse manure. Then we threw in the pansies and violas. We let them reseed, but add about a flat or so every year. This works great as a living mulch. Since we have great drainage from the sand, nothing stays too wet, and the pansies seem to keep the soil a little bit cooler. They've helped us to save plants that like damp and plants that like dry. I like to think of them as little ambassadors telling everyone to get along. Added bonuses are that I don't have to look at dirt, they help to squeeze out the weeds, and since it's a little cooler they bloom steadily all summer long!!