Anyone above the age of OSRS GP 72 may start planting Calquats which patch is located to the north on Tai Bwo Wannai on Karamja. The tree is able to grow for over 21 hours but is an ideal complement to other methods because it offers 12,5k exp being taken down. Calquat tree seeds are also among cheap ones so it's no big cost to buy. These seeds are available from Grand Exchange which is the most efficient option.
If you have already passed 85, you are now able to plant one more special tree which is Celastrus. The Celastrus tree patch can be found in the third level of the guild known as the Farming guild. Although it's quite costly seeds, it will not give you any more experience than the Calquat tree. Growth time is around 13,5 hours so overall it can be a great way to boost your experience however it should only be used by those who have spare gold to cultivate and who want to get maximum achievable experience during the day.
Begin with Varrock which is where OSRS gold you will find a trees a bit further to the east of the castle. You can teleport into Tree Gnome Stronghold by using the option of Spirit Tree and Slayer Ring and plant what you have. Make use of Falador to teleport as well as the farm tree patch to get there. Connect to Lumbridge and then the farm tree patch there . Then go to Taverley where you will find another. The last patch of trees is in a farming guild but you will need 45 farming or 60% Hosidius favor in order to gain access to it.