Musnad Ahmad 1060:23

Sa'id ibn Mansur—meaning al-Khurasani—narrated to us, Abdullah ibn Abd al-Aziz al-Laythi narrated to us, he said: I heard Ibn Shihab saying: I bear witness regarding 'Ata' ibn Yazid al-Laythi that he narrated to him, from Abu Ayyub al-Ansari, from the Messenger of Allah, peace and blessings of Allah be upon him, that he said: "There is no man who plants a plant except that Allah writes for him a reward equal to the amount of fruit that comes out of that plant."