Put the summary of the bug you're having here
Some of the new plants (and old ones) can't be placed in flowerpots. Some plants when placed in flowerpots, aren't causing the block to update to show the plant in the pot, and don't become visible until something else causes the block to update.
What I expected to happen was...:
Placing a new flowerpot, and placing one of the new plants using right-click, I expected the new plant to appear in the pot.
What actually happened was...:
If I applied an Oak Sapling, Dandelion, Poppy, Brown Mushroom, Red Mushroom, Cactus, Dead Bush, nothing appeared in the flowerpot, until a block next to it was disturbed (such as by destroying the block next to it).
Sunflower, Lilac, Large Fern, Grass, Rose Bush, and Peony could not be placed in flowerpots at all.
Spruce, Birch, and Jungle Saplings, Fern, Blue Orchid, Allium, Azure Bluet, Red Tulip, Orange Tulip, White Tulip, Pink Tulip, and Oxeye Daisy all worked as expected.
Steps to Reproduce:
1. Place flowerpot
2. Right click flower pot while holding plant
3. Break block next to flowerpot to force a block update