you needed a container type plant. If you want to grow big ones you need at least 5 gal of dirt IMO. Of course fertilize/ammend soil and dont over water!

16" pots are usually too small and/or shallow. Plants quickly become root bound. 5 gallons is the minimum recommended and bigger is MUCH better. Plus you have to feed them regularly when in containers as the the nutrients flush out every time you water.

Nothing wrong with the variety you used although other varieties that are bred for containers tend to work better. But you need bigger containers and a regular feeding program when using containers.

Dave

You're overwatering. Give 'em a break until they dry out a bit.