I could do with abit of advice here. I've neglected my garden for several years now and its seriously become overgrown. Plants that I am concerned about are choiysa, spring flowering clematis, camelia and forsythia, I know some of those plants can't withstand severe pruning but I haven't got much choice. What will happen if I do it anyway, will my plants die
If it flowers before June - prune right after flowering. If it blooms later than June, prune January to March. (if that helps at all) You cut rock roses back hard after first flush of flowers to induce another flowering, and to prolong the life of the plant.
choiysa, spring flowering clematis, camelia and forsythia...are mostly spring flowering. if you prune them now you wont get any flowers this year. also the new growth will be vulnerable to frost damage. Better to cut them back after they have flowered. the forsythia will be Ok cut back hard. go easy on the evergreens