The general recommendation is to do it after the 21st of July. Part of the reason for this is that it is unlikely to have heavy frost after this date.
The way I have my garden maintenance service teams prune is as follows:
- First you cut off the top growth, this gives you a better view of the framework of the bush.
- Then you remove dead, diseased, old and misshapen stems.
- You remove older stems which are usually a grey-brown colour, and keep the newer stems (a paler green or sometimes with a reddish tinge
- Then you select three to five stems from the bottom of the bush, these stems should form a cup shape, with enough spacing between the stems. The selected stems should be cut of at about knee height. Remove all the other stems.
- After cleaning up, spray the bush with lime sulphur mixed according to the specifications on the container. Usually a ratio of 8:1. After two weeks you can spray the bushes again, but at half strength. (Remember that you need to use fresh lime sulphur every year, as it does go off)
A&F Complex Management - Garden, Cleaning, Maintenance Service