It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) recited the qunut for one month after the bowing (ruku'); he (peace and blessings be upon him) would supplicate against some of the tribes of the Arabs.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3122