This is not Aloe arborescens, but another aloe. I would like to move it to the generic entry for Aloe. Please let me know if you would have a problem with that.
I realize this is a Wikimedia file but the plant is misidentified. The flowers are not a match. Also the leaves are wide, the posture is erect, and the plant is solitary... none of those are characteristics of arborescens.