Re-Fertilizer is a craftable material in ARK: Survival Evolved. It can re-grow plants, trees and even rocks that have been harvested previously.
To use it, place it into your hotbar and then use the item in the requested area, or use E, , when activated in your inventory.
The area of effect is quite small, it is not much more than a single foundation. And it has a period of non-working (If you cut down the tree it will not grow immediately even if you use Re-Fertilizer. You need to wait some time before it will work)
- Beware while using Re-Fertilizer, you can regrow a tree or a rock on you and get stuck in it. This might lead to the death of your character, where you would be able to retrieve your inventory on your dead body. It can also lead to the destruction of your body by the anti-meshing system on Official Servers, and as a consequence losing the entirety of your inventory.