Planting Tree Cuttings/Saplings/CactusFollow

I have seen some good guides on gardening but nothing on Tree Sapling, Tree Cuttings or Cactus Stems. They appear in similar looking bags and I have heard rumors about these items being related to gardening, but I have not found any information yet. The item search on Allakhazam is returning no information.

Anyone know of any guide? These things are pricy and is like to get some idea of results before investing 18,000 gil into a bag of mystery seeds.

Thanks