IIRC plants and enemies only appear after you find them or fight them, respectively, for the first time, not before. Even then, one of the alchemical ingredients I needed was on the forest path, which only unlocks after defeating the bandits. I simply was not interested in doing their quest for a long while.
I started out with the Lizards, and after their main quest began to focus on the rat men and werewolves simultaneously. So I had a lot of areas unlocked and eventually as the quest piled up I got confused as to where to go next because they started demanding ingredients I didn't have access to yet with no real indication that I recall on where to find them.
A reference guide at the house left by your missing master that hints at or tells you where ingredients are even if you have yet to find them or unlock the area they are in would be a nice touch IMO. It makes sense in-game and avoids being too hand holdy at the same time.
Unexplored areas (some of them not the hidden stuff like the ruins) topside should be marked on the map but not accessible (Lore wise it'd make sense for an alchemical master who travels all over the place to leave behind a fuller map in his house of established regions and pathways). Practically, that'll give players some direction in the future to access the stuff they'd prefer to do first without needing to resort to online guides or quest grinding.
AKA I need X,Y,Z it can be found at B, which is behind the bandit camp. And there you go. You still need to navigate the quest on your own and figure out if B really is the reason you can't access the area.