Responsa for Bava Batra 54:4

רבן שמעון בן גמליאל אומר הגדל בחיוב חייב הגדל בפטור פטור

fruit subject to tithe and fruit not subject to tithe are mixed up in it. This is the opinion of Rabbi. Rabban Simeon b. Gamaliel, however, says that that which grows where the obligation extends [i.e., in Eretz Yisrael] is liable and that which grows where the obligation does not extend [i.e.. outside Eretz Yisrael] is not liable.' The difference of opinion between them only consists in this, does it not, that the latter holds that we can decide retrospectively [which fruit belongs to which root] and the former holds that we cannot, but both agree that anything which grows where the obligation does not extend is not liable?<span class="x" onmousemove="('comment',' Even within 16 cubits of the boundary, and we do not say that it sucks from Eretz Yisrael. ');">⁴</span>

Teshuvot Maharam