Can you grow daphne in a flower pot versus the ground?

You can, but it will be very important to find some way to keep the pot cool. Daphne require a cool root run, which is sometimes hard to manage with containers. Try placing other pots closely around the pot the Daphne is growing in, so that they keep the pot shaded. Also, be sure that your pot has superb drainage - porous potting soil, lots of drainage holes, raised off the ground by something that allows water to run through freely. Daphnes die quickly of root rot if their soil isn't exceptionally well-drained.