History of Endotherapy
Ibn Al Awam (13th century) was an “agronomist engineer” from Seville, who wrote the treatise Kitab al-Filaha (The Book of Agriculture). Disappeared for 6 centuries, in the 18th century it was reprinted and is a reference in world agriculture. Inside, he talks about how, through a slit at the base of the trunk, it was possible to improve the future and color the flowers.
It can be inferred from this text that it was a fairly widespread practice among agronomists of the time.