Potted plants add a lush swatch of green to a room, but the soil they grow in has never done much for any decor. A layer of small, round pebbles arranged over the soil's surface looks as neat and tidy as a Japanese garden and helps keep the ground beneath it moist and shady, which is just the way most houseplants like it. Bags of small black or white river pebbles can be bought from plant or garden stores and arranged in concentric circles in your pots.