פירוש על עבודה זרה 90:3

In this midrash R. Yose son of R. Yehudah largely reiterates the midrash the Mishnah presented, but adds in that although the verse says “under every green tree” and we might have read this to say, “and the tree cannot be their god,” we do not read the verse this way because the Torah specifically says that their asherah trees must be burned.
The Talmud does not here explain how we know that this tree was first planted and only later worshipped. This will be explained in tomorrow’s section.