So I decided (due to my schedule the rest of the week) that it would be well worth it personally for me pay the 70 gems and start Chapter 7 early so I could Adventure all day and stock up on the extra bushes, shrubs and saplings. I'm pleased to announce that the very first Adventure I completed after finishing Ch.7-2 gave me a Cotton Candy Bush and I've gotten at least one of each of the others as well.
Keep an eye on your inventory because the Crate will still only contain the Chocolate Rock after 7-2. The extra items that we can collect from will be dropped with the regular Adventure Drops such as the Chocolate Ore, Lollipop, Crystal Candy, etc.