Mississippi,
United States 
I have two very old camelia bushes.They belonged to my grandparents and are probably at least 30 years old. However, I would almost say they are trees because one of them is 12 feet tall. I am wondering how should I prune such large bushes.
23 Mar, 2010
First ask yourself, do I really need to prune them? Are you wanting to prune them because they obscure a view or are too large and restrict access, have become misshapen or look out of place?
They can be pruned, normally just after flowering (spring flowered group). You can renovate too which means cutting hard back into old wood leaving no leaves or small twigs at all. Though drastic, they will re-shoot very quickly and recover. They will not flower for at least three years after this but it will renovate an old bush.
ps 15ft is the end of shrubdom and the beginning of treedom :-)
23 Mar, 2010