Musnad Abu Ya'la al-Mawsili 3:195

Shayban narrated to us, Masrur ibn Sa'id al-Tamimi narrated to us, Abd al-Rahman al-Awza'i narrated to us, from Urwah ibn Ruwaym, from Ali ibn Abi Talib, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Honor your paternal aunt, the date palm, for it was created from the clay from which Adam was created. And there is no tree that pollinates other than it." And the Messenger of Allah (peace and blessings of Allah be upon him) said: "Feed your women fresh dates (al-rutab). If there are no fresh dates, then dried dates (al-tamr). And there is no tree more honorable to Allah than a tree under which Maryam bint Imran descended."