Negative commandment · Lo Ta’aseh #13 of 613
Not to plant a tree on the Temple [premises]
שלא ליטע אילן במקדש
The verse · Devarim 16:21
לֹא־תִטַּע לְךָ אֲשֵׁרָה כׇּל־עֵץ אֵצֶל מִזְבַּח ה׳ אֱלֹהֶיךָ אֲשֶׁר תַּעֲשֶׂה־לָּךְ
“Thou shalt not plant thee an ashera of any tree near the altar of the Lord thy God, which thou shalt make thee.”
The Rambam’s words
Not to plant a tree on the Temple [premises], as [Deuteronomy 16:21] states: "Do not plant an asherah or any other tree...."
שלא ליטע אילן במקדש, שנאמר "לא תיטע לך אשרה, כל עץ" (דברים טז,כא).
Who & when
“And this prohibition is practiced whether by males or whether by females.”
Where in the Mishneh Torah
Hilchot Foreign Worship and Customs of the Nations הלכות עבודה זרה וחוקות הגויים