Question
I have a varigated Holly which is losing its leaves.  The end of the branches then turn black.  The top of of this large bush is healthy but the lower section is completely bare.  The holly is over 25 years old and there are 2 sections of both leaves and stems which are growing in cream.

Answer
Dear Alison, It sounds like your holly may have scale, a common insect pest on holly.  These are unmoving insects which look like bumps on the stems and leaves of the plant and cause the plant to lose leaves, cause black sooty foliage from the honeydew they secrete, and will eventually kill the plant.  This is almost definitely what is wrong with your holly.  The scale can be white, black or brown, but it will be on the stems and growing tips and under the leaves.  To get rid of it, spray the entire plant, especially under the leaves with horticultural oil, or biorganic oil.  You should be able to find these products at your gardening center.  Regular insecticides don't work well on scale because they are protected under the shell like covering, but the oil will smother them. You will have to spray several times about a week apart to get complete control of them.  You will know they are dying when a moderate blast of water will loosen and remove them from the plant.  Now about the two sections of holly that are growing in cream.  If there is no green on the leaves, I would cut them out, because they will sap the bush of strength and eventually die out anyway.  Plants, even variegated ones, need chlorophyll to process the sunlight to give it food.  When there is no chlorophyll in an area of the plant, that section must get its nourishment from the rest of the plant.  At some point the stress gets too great and the entire plant will weaken, or the whiter shoots will start to die.  I would cut those out and go for a more uniform appearance.  I hope this information helps and addresses your problems, but write back if you think that something other than scale might be harming your plant.  Good luck, Melissa