castor oil plant disease

My my large castor oil plant has got a disease. There is very limited new seasonal growth. New shoots curl and turn black. Some leaf stems  look as though they have been scorched. Some leaves have turned black and become brittle. Is there any hope for it? It has been in the garden for over 30 years. We had to remove a golden conifer from a position adjacent to the castor oil plant in Autumn. 

Peter