This might not be practical but have you asked a garden centre for advice? My local garden centre is full of staff who can provide useful suggestions, tips and information on all aspects of gardening matters. The employees can deal with your query and offer advice as well. You can even buy plants etc.
Additionally this is another gardening thread that might be useful to look at
https://www.mumsnet.com/Talk/gardening.
What is the issue with the rose bush? Does it need to be pruned?