Reference for Sotah 86:4
כרם אין לי אלא כרם מנין לרבות חמשה אילני מאכל ואפילו משאר מינין תלמוד לומר אשר נטע יכול שאני מרבה הנוטע ארבעה אילני מאכל וחמשה אילני סרק תלמוד לומר כרם
What is an instance of this permitted grafting? If I say a young shoot on a young shoot, it follows that he ought to return home on account of [planting] the first young shoot! It must therefore be [grafting] a young shoot on an old stem. But R. Abbahu has said: If he grafted a young shoot on an old stem, the young shoot is annulled by the old stem and the law of <i>'orlah</i><span class="x" onmousemove="('comment',' Lit., 'circumcision', the Law of Lev. XIX, 23 forbidding the enjoyment of the fruit of a tree during the first three years of growth. Since this regulation does not apply to a young shoot grafted on an old stem, it is not regarded as a new planting. ');"><sup>3</sup></span>