Hello my griselinia's have been dying. They get yellow leaves and woobbly in the ground. from what i can gather it could be a combination of things but one thing which i think is the most major problem is the trunk gets a ring around it like my husband has attacked it with the weed-eater. It goes right around the trunk and the bark falls off, these trees are no more than 2 years old and about a meter high?? I have lost 3 already, how can i stop from losing anymore. thanks