I have discovered over time that these roses take nearly 3 years to get well established. They vary greatly in habit, which means the pruning instructions also vary, but in general the information I'm giving you now is very accurate for Cork gardens. Soil conditions will differ, but these guidelines will help you to produce well shaped bushes that will hold these very heavy flowers. The main thing is to establish a good shape and this is really what takes time.
You should continuously prune throughout the summer, only cutting back stems by about 4 inches, but you are repeating this cutting back throughout the first few years. Personally, I don't approve of just one cutting back in winter or spring - cut back continuously from spring, never cutting back more than 4 inches. Keep shaping the bush to a good sturdy shape with nice thick strong stems - the latter is imperative to the overall success of your bush.
Why do some roses develop week spindly stems?
Well, this is partly down to the pruning I have spoken about, but also feeding. Too much nitrogen will cause weak growth. I find Roses need a lot of feeding - a little and often is the best, not one feed in spring and nothing else. Again, this depends on your soil. Some soil will be richer than others, so it is a good idea is a good idea to do a soil test – then you will know exactly what your requirements are!
My Proven Feeding Recipe
Use slow release feed in February – 2 tablespoons per bush, then mulch (with a product of your choice).
When you know the weather has picked up in spring, feed with Sudden Impact & Dried Blood – a fistful every 2 weeks.
By early June, your roses should be flowering well and no more feeding will be necessary until August, when I would repeat the slow release feed application.
Weak Roses or ones in need of extra feeding:
Repeat as above, but include liquid feeds of Maxi-Crop plant tonic once a week. This will get the root system strong and vigorous and will transform your rose bush!