Posted: 08/10/2012 at 15:49
There are so many commercial preparations available that my advise to you would be to go to a good garden centre where you will find products - usually containing magnesium or manganese sulphate - which will say ' for yellowing of the leaves'.They will have instructions on how to use. Also, if you take one of the leaves with you a member of staff should be able to help you further. Do bear in mind though, that you may have to keep the treatment up continually throughout the lifetime of the plant and you may wish to consider an alternative - I landed up getting rid of several large laurels because they were never going to look good and were continually loosing the older leaves that they just looked unsightly. Good luck!