Aloe petricola grows a single, long raceme in younger plants, a small panicle of two or three later, while old plants may produce up to six. The orange-red or dull red buds undergo a colour change upon opening, transforming to greenish yellow and white-lined open flowers or perianths.

This happens in winter from before midwinter.

The bicolour characteristic is shared with a number of other aloes (Van Wyk and Smith, 2003).