Hey, can someone help me, I've built my alchemy bit, but its not letting me gather the cactus, I keep dropping my villager on it and she see's it but doesn't do anything, I've tried this loads of times now but nothings happening =[

Sometimes it works better if you drop a villager near, but not directly on, the herbs. You can also use kids to gather herbs, and they do it much faster than most adults.

drop the villager at the base of the cactus it usally works