An Ivory Plant may turn yellow due to a number of things such as too much water,not enough water,
insufficient sunlight and lack of nutrition. Insect infestation may also cause this.
Your ivory plant turns yellow because of not getting direct sunlight else it may not have
the proper water. It does not have the equitable strength to stand in the place. You may have
to put it insecticide because the insects will decay the plant. So the plant turns yellow in
color
