A long shot: it looks rather vine-like and leaves resemble some types of kiwi-fruit vine leaves (broad spear-shaped leaves) so could it be that perhaps? Difficult to make out whether leaves have pointed ends, but, then again, some kiwi vines have less pronounced tip to the leaves. As I seem to be allergic to the fruit, I have never tried to grow and I have never actually seen the plant in the flesh, but I offer the thought in case you have ever tried planting seeds or discarded pulp into compost.