The main reason we prune our roses is to maintain a tidy, well balanced plant.The best time to prune your roses is in the Winter time when the rose bush has gone into it’s Winter dormancy. June or July are generally the preferred months but some folk will prune in August, it all depends on where you live in the country.
Use sharp secateurs when you prune to prevent damage to the bush.
Ideally when you prune, you will remove all wind damaged, insect damaged and dead stems first, also any stems that are crossing over each other through the middle of the bush. By removing weak & crossing over stems from the middle of the bush, you are helping to develope an open, airy bush that will allow good air flow & light into the heart of the rose thus helping to maintain good health. Every one has their preferred height to prune a rose to but personally, I prune about 1/2 of the height off the bush. Try to cut to an outside facing bud as the new growth will grow up & outwards, helping to develop an open, airy rose bush.
When you trim off old flowers ( dead head) off your rose bushes at the end of each flush of flowers, don’t just remove the flower, cut further down the stem- about the length from your elbow to your wrist and again to an outward facing bud. This is a little mini prune each time and the resulting new growth will produce lovely strong canes with large blooms once again. If you do only remove the flower itself, the next flush of flowers will produce smaller blooms on weaker, twiggy growth.
Modern climbers will need pruning during Winter.
Ramblers however, are different and need to be pruned during Summer after their main flowering. Because Ramblers generally only flower once in the season, if they are pruned in Summer (January), they will then send up their new growth over the rest of Summer which you will train, then these canes will have flowers on them the following Spring. If you prune Ramblers during the Winter, you will be removing the new rose canes that will be carrying the next flush of flowers and your rose will probably not flower that season.