is this for them to eat, or to look pretty? it'll need to be something they don't like if you want it to look nice, and in any case something robust if it's to last more than a day or two! In my experience the compost gets turfed out whatever the plant , so something with strong roots is a must .
Also, what kind of soil do you have? We have clay here so not too many things grow unless we buy soil. And like PP said, pots will be used as a dust bath...