RobertaMary, it is best not to let your dog chew on plants in the garden, as quite a few are toxic to dogs and can make them quite ill, including some tree bark. Two of ours are "gardeners", so like chewing on anything and everything in the garden and the only way I have been able to stop them is to spray the plants and planters with "Get Off" which you can buy in an y good pet shop. Dog don't like the smell of this stuff and so learn to leave the plants / tree alone. But you will have to keep spraying it regularly for quite a while until the dog has leaned to stay away. Our Keeva became very ill when she dug a huge hole in the garden and deep down found old Clematis roots. She ate them and her lips and eyes puffed up and went very red and sore. It took months to get this sorted, so please do be careful. Most people are unaware that they may have plants in their gardens that are poisonous to dogs. Better to be safe and deter them from chewing asap.