My large Christmas cactus isn't doing well.
Healthy branches turn yellow and eventually brown and die.
Meanwhile, smaller, younger Christmas cacti in my collection look fine. Let's get to the root of the problem before making any recommendations. Gently slip your cactus out of the pot and examine its roots. If they are dark brown or black and their skin slips off easily, suspect root rot. Overwatering or poor drainage can cause this condition to occur.