Pruning roses is one of those jobs people tend to get into a panic about, but it's really quite simple as long as you follow the basic rules...
Bush Roses and Hybrid T
I tend to prune shrub roses from about January through to March, which is fine, as long as you don't prune if cold weather is expected.
I start with removing the three Ds: that dead, diseased or dying wood, as well as removing crossing branches, which could be rubbing one another.
Start by removing larger stems to within 5-7 buds from the soil level (or higher if height is desired). Remember, you are in control of the plant - you decide on the height! Less vigorous shoots need to be pruned harder, which will help make them more vigorous next year. Always prune to an inward facing bud if possible to ensure the rose is kept more compact.
If there is congestion within the centre of the plants, then try to remove stems to help this. I was always told at college ''if in doubt, cut it out'' which I believe means it is better to prune a rose hard as this tends to produce better re-growth and flowering.
Climbers or ramblers can be trained onto a structure or wall using trellis or wires. The way they are pruned differs somewhat from bush or Hybrid Ts, as your aim is normally to cover the wall or structure, meaning you want the rose to grow outwards.
Start by selecting which stems are to be kept to tie onto the trellis to form new framework. Any stems which are in the wrong place, or growing in the wrong direction can be pruned off and shortened. Flowered shoots can be trimmed back by about half or three quarters length.
As you work through the plant, tie in stems into gaps or remove older, diseased, dead or dying stems and replace with younger stems. Try to tie in stems as near to horizontal as possible - this will create many more flowers the following summer.
On larger, older climbing roses, I try to prune one main stem from the base or near the base every year to help promote new growth. This is not always possible, but is good practice to keep the rose living as long as possible.
Remember: NEVER compost rose prunings as this can spread disease to other roses throughout the garden when the compost gets spread. Either burn or dispose in a green waste bin.