All species are pretty tough if temperature is upper than icing point, 0 Celsius. Theya are not good at high temperature. However, leaves of some species die out to be brown in the next day if it becomes lower than icing point, i.e. 0 Celsius. with water. This trouble tends to happen when we water in winter. In the worst case, all leaves of the foliage is fell off to be dead. T. atroviridipetala in the photograph, T. concolor, and T. circinatoides are expecially weak to this trouble.