Goes without saying, but the art in this is incredible. Spectacular. (Though I agree that the stark white square player was a bit jarring among all the beautiful scenery.)
The parallax also looked really nice, though I would have liked some damping on the movement. For my eyes/sinuses.
In terms of controls, I would have liked to have a separation between the clicking to find things and the moving; I was often clicking on things to see if it's a thing, and then moving. It's not a huge deal, but a little annoying. (E.g. having left click be for selecting things and right click for moving would have solved this.)
I also wonder if it would have felt cooler to have the player add the plants to the book by examining things rather than already knowing all the ones they're looking for? (Or a textual description, which turns into a sketch once you find it?) I think a sense of discovery is paramount to what this game seems to be about, so leaving a bit more mystery to start out with might have been good? (Also, I feel like my ability to come up with a good name for a plant massively improves once I see the poem; i.e. having the players "discover" new plants and only then sketch and name them would have been cool.)
I think I made it to the end; your description says I'll unlock a poem if I find all the plants, but I don't think I did (unless you meant the individual poems for each separate plant, which I did enjoy for all four).
Anyway, what a beautiful and chill experience. Very cool.
(Played the jam build)