Nafi' narrates from Ibn Umar (may Allah be pleased with them both): "There is no zakah on any wealth until a year has passed over it."
This is the correct version, as mawquf (a saying of Ibn Umar). Baqiyyah narrated it from Isma'il bin Ayyash from Ubaydullah bin Umar as marfu' (attributed to the Prophet), and that is not correct.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7322