I have this very pretty terra cotta planter. It is round, about 14 inches in diameter, but only 5 inches deep. What would work in it?
Succulents! See the link to another thread.
Here is a link that might be useful: shallow container plants
The shallower the container, the more important it is that you use a well-aerated and fast draining soil. I like succulents & cacti in shallow containers
but there's no reason to feel limited to those types of plants