Roses should be pruned each spring. Cutting back rose canes (i.e. the stems/branches) every year helps to foster healthy, good-looking plants and encourage more blooms. The time to prune is in the spring, once you can start to see buds emerging.
The most important piece of equipment for pruning roses is a very sharp pair of secateurs. Dull secateurs are frustrating to use and can cause damage to plants.
The second important tool is a pencil.
A pencil is going to show you how much of your rose bush you should be cutting back.
The general rule is that any canes thicker than a pencil should be cut back to about 10 buds or at about 11″ high.
Any canes thinner than a pencil should be cut back to about 3″ or less.
The above photo shows a cane that is thinner than a pencil, so I want to cut it back to about 3″ in length.
The cut should be made just above an emerging bud.
Don’t cut a long ways above the bud, as large pieces of stem remaining above the bud will die off or rot.
But the cut also can’t be so close to the bud that you damage it.
The above photo shows a nice clean cut, at about the right point.
Exceptions to the pencil rule
If you’re growing climbing roses and you have healthy thick canes (like the one in the first photo that was thicker than a pencil) you can choose to leave them taller than 11″ or 10 buds. The cane in that photo is a climbing rose and I pruned it to a height of about 2′.
Tiny canes, anything smaller than a piece of cooked spaghetti can just be sheared off or trimmed at the bud closest to the main cane. They’re so small that they’re not going to amount to much
Pruning for shape
Look at the direction that the bud you’re going to cut above is pointing. That is the direction that the new cane is going to grow. In the photo above, the bud is pointing off to the right and this is the direction the new branch will take. If I had cut the cane one bud lower, the branch that emerged would be pointing towards the camera.
Consider this as you decide where to make your cuts–your decisions will determine the shape of your mature rose bush. For most roses, you’re trying to guide the plant towards a vase-like shape.
I have a lot of roses and some of them have pickier thorns than others. I wear thick gloves (usually called rose gloves) that extend almost to my elbows. I highly recommend getting a pair if you have a number of plants to deal with. I also wear jeans and a thick canvas jacket/shirt on pruning days.
Be sure to pick up all of the canes you prune off and dispose of them. It’s no fun to be weeding or happily digging with bare hands near your roses and come in contact with a piece of old rose cane. It’s equally unpleasant to kneel down for a moment (especially while wearing shorts) and “find” the rose cane pieces you didn’t bother to tidy up earlier in the season (or the season before). After many such experiences I have finally learned to drag a yard waste bag along with me as I prune.
And the final tip for pruning roses (or any plant): you can always cut more off but you can’t glue a piece back on!