Operating System: Windows 8, Java: 1.8.0_25 64 bit
I was in a superflat world with the preset 3;64*minecraft:iron_block;127; and I attempted in both creative and survival to place a sapling fern and pink tulip into flower pots.
What I expected to happen was the flower pot to change data and display the plant.
What actually happened was that the flower pot remained empty.
How to reproduce:
1. Place flower pot.
2. Attempt to add plant.