It is narrated from Sayyiduna al-Hasan bin Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Date palms and other trees are a blessing for their owners and for their offspring after them, provided that they are grateful to Allah."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2722