It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that when the Prophet (peace and blessings be upon him) intended to relieve himself, he would not lift his garment until he was close to the ground.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 458
Another hadith with the same meaning, except that it has these words: "until he reached the ground." Hasan li-ghayrihi (sound due to supporting narrations).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 459
It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that when the Messenger of Allah (peace and blessings be upon him) intended to relieve himself, he (peace and blessings be upon him) would go far away, and he would not lift his clothes until he was close to the ground.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 460