Ixora can thrive in cold temperatures but extra cold weather can cause them to drop their leaves.
The dwarf red is the most cold stable, with the pink, white and orange varieties more sensitive.
Be careful not to overwater while the plant is either still dormant or under stress.
Watch for new growth to began and then resume watering and fertilizer schedule.
In the case that you do not began to see new leaves growing back, the plants may have died off.
The plants should be planted in a well draining soil and be kept moist.