Aeonium Care: Leaves that Curl up and Die
If the leaves of your aeonium plants curl up and die, then you have a problem with either watering or temperature. They like lots of water and a mild temperature.
Refrain from pruning any of these discolored leaves unless they are dry and brittle. The aeonium wilts dramatically as a defense mechanism and can fully recover with a bit of care.
Your aeonium is a succulent that needs moist soil at all times. If its leaves are wilting and are deeply discolored, you are either not watering it enough or consistently enough. If the soil has been dry for more than two days, then the plant may take weeks to recover. An automatic drip system may be needed for this plant if you plan on leaving it alone.
If your aeonium's leaves are curling but have retained most of their color, then they are simply protecting themselves from unpleasant weather. The effect is the same whether the climate is too cold or too hot. In the hot summer you can protect your aeonium with a sheer garden cloth. This will filter the sunlight. Keep the cloth on until temperatures become more mild. If your aeonium is in a spot that receives direct sunlight for most of the day, consider replanting it somewhere else.
Aeonium is a winter grower. It needs a moderate, moist winter that does not have frost. Because the aeonium is so sensitive to freezing temperatures, mulching will not help. If you have already planted your aeonium in a cold climate, there is nothing that can protect it other than converting it to an indoor potted plant.