Really great use of public domain art here.
There's a lot of really cool lore baked into this. The floral theme is used in some really cool ways here and is consistent enough in the adventure to not be forgotten about. The Glasshouse is a really interesting space with its desert and tundra.
I really like the way the armor and the poison work. Sir Dent De Lion and the Snapdragon are both excellent inclusions. If the PCs aren't already seeking them out or running into them, I might fudge those encounter dice a bit to make sure they make an appearance.
The hook where the PCs are working with or are Merchants of Ash is really compelling, especially since I have a feeling a lot of players will gravitate towards sympathizing with The Green Hand.