I am an organic rose gardener and have material on the web about my organic practices. Though I don't have any special techniques about pruning, it's a topic that many people ask about, so I thought I would create a resource here about rose pruning that I would illustrate with pictures from my garden, and include references for additional information. Do visit my main rose page and my personal home page!
Keep in mind that my experiences are shaped by growing roses in North Carolina ( USDA agricultural zone 7B), where we typically do have some frost, often in late December or early January, and where spring seems to start in late February with a last frost date of April 15. You'll want to get some local advise from a local rose society or home garden expert. Pruning is covered in any book that discusses rose culture.
It is important to prune according to the type of rose you have; more on this later. In general, pruning helps keep the rose plant healthy, encourages more (light or moderate pruning) or larger (more severe pruning, as is commonly done with hybrid teas) blooms, and allows you to help shape the bush.
As rose canes age, they are able to produce a decreasing number of flowers. If you take a look at your rose bush's canes, you'll see that the older canes seem harder and "weathered"; the cane's useful life is about 3 years, and after this point, it becomes difficult for new growth to emerge from the hardened bark. Annual pruning encourages the bush to put out "basal breaks" near the bottom that result in new canes. Especially for modern hybrid tea roses that may be susceptible to disease, pruning also opens up the center of the bush to allow better air circulation, and, for roses that are grafted onto the rootstock of another variety, to allow the bud union (out of which new canes come) to get more sunlight.
An ideal time for spring pruning is after the last hard frost (but not as late as the last possible frost date). Your roses should have red bud eyes (from whence new growth will emerge) and perhaps up to a quarter to half inch of new growth, indicating that dormancy is breaking. A good rule of thumb is to prune around the time when forsythia is blooming (late February or early March here in Durham, North Carolina USA). For bushes like hybrid teas where you may choose severe pruning, never fear - the pruning may look like a short-term butchering, but will stimulate good new growth.
You should expect blooms about 6-8 weeks after pruning; keep this in mind if you need roses for a rose show or special event. If you prune too early, you risk late winter freezes of the new growth you have encouraged, which will die back. Pruning too late saps the bush's energy - it will have expended effort putting up new growth which will amount to nothing when you prune it off.
During the growing season, you may want to cut and bring in your lovely roses, particularly if they are long-stemmed hybrid teas (you'll ideally want to follow the 5-leaflet rule - from the flower, look down the stem to the second leaf that has 5-leaflets, and cut just above; as the stems get longer over the season, you can cut above a third or fourth such 5-leaflet). You should also "deadhead", or remove old blossoms that you've left for garden display, so the bush doesn't get the message that it's time to go to seed and prepare for dormancy. At any time, you should remove dead wood, cutting till you get to healthy white wood or back to the base (bud union if grafted), if you want to remove the cane entirely, perhaps to open up the bush or remove one of two canes that are too close to each other.
For hybrid teas, you will want to do some winter pruning when you're getting your roses ready for dormancy (except possibly in mild frost-free climates - but even there, some cleanup pruning may be in order; check with local sources). In the late autumn or early winter around the time blooms have become frost bitten and the bush appears to have gone into dormancy and stopped growing, you will want to prune your hybrid teas. This is an easy prune and its purpose is not to encourage new growth (remember, we have waited till the bush has achieved dormancy), but to protect the bush from damage from winter winds which could cause canes to rub against each other (causing potential cuts or blisters) or potentially loosen the roots. Simply cut back your hybrid teas to approximately waist high. No need for finesse - just cut to perhaps two or three feet from the ground.
Some newcomers to roses approach pruning with trepidation. Roses are surprisingly hardy to pruning. You obviously need to understand pruning basics and know the kind of bush you are pruning. When pruning, you need to justify each cut, but if you find you are spending more than 10-15 minutes pruning a rose bush, you are probably being overly cautious. If you want to get the most out of growing roses, it's a good idea to join a local rose society, and they will often have a program in late winter or early spring about pruning; try such seminars/demos out a few times to build up your confidence.
Roses in general are very forgiving to pruning, and in fact many varieties rely on pruning to maintain good health, but you must know what kind of rose bush you have before you start to cut. The way you would prune an old garden rose is quite different than the way you would a modern hybrid tea.
If you are a novice and need some help identifying your rose, look carefully to see if it has a tag - it could be hidden in the bottom of an overgrown rose or under a thin layer of dirt. Lacking that, see if a local garden or horticulture store or center can help. Of course, your local rose society can help!
Hybrid teas are the long-stemmed cutting rose that seems to be the most popular type of rose for the past several decades. They are characterized by big flowers that have high centers with pointed buds, a large petal count, and good repeat blooming.
The best known and first (1954) Grandiflora, created by crossing a hybrid tea with a floribunda, is Queen Elizabeth. It has the typical high-centered and large flowers of hybrid teas, but in clusters like floribundas, and they tend to grow tall.
Hybrid teas and floribundas are pruned similarly. Around the time when forsythia is blooming, as described above, you will want to do a spring prune. Your roses should be mulched, and you'll want to start by pulling the mulch away from the center, so you can see the full form. Here, you can see one of my Double Delight hybrid teas before pruning, and with the mulch being pulled away.
After you have sterilized your shears by dipping in hydrogen peroxide or a dilute
bleach solution, start pruning by removing any dead wood; as with many garden shrubs and trees
(I don't know of any exceptions), you can and should remove any dead wood at anytime
of the year. Here you can see me removing a dead cane (if you look carefully; you
can click on any of the pictures to see a larger version).
If you have grafted roses, cut off at their origin any suckers, or growth coming from the base rootstock below the graft - again, you should do this anytime suckers show up, or they will suck energy into producing roses from the rootstock, not the graft.
Hybrid teas (and grandifloras) are less disease prone if their centers are empty, so that the bush has good air circulation. Open up the center by removing canes that aren't outward growing. Also, crossing canes are a bad idea; in the wind, canes which touch can rub against each other and open up wounds. If you have crossing canes, completely remove all but one.
Now you should be able to better see what you have to work with. You have a choice of light, moderate, or heavy pruning. Light pruning is like a haircut; you would leave many of the canes and then snip off maybe 20% of the length of each cane. You will get roses sooner than with the other styles of pruning, but will get smaller roses with less pleasing form. For own-root roses, you may want to favor light or moderate pruning for the first two seasons.
Most people choose moderate or severe pruning. You will get larger and better looking roses, but it will take a bit longer for the bush to have the energy to put out blossoms. Folks who seek excellent form for rose shows favor severe pruning. I tend to the severe side of moderate, whatever that means! For either moderate or severe pruning, pick 3-6 canes with reasonable thickness that together form a bowl shape or hand holding a ball, and remove all the other canes. If you only have one or two strong canes, leave just those and don't worry about the preference for more. Remember that rose stems will be no wider than the cane they come from, so when you're all done, you should be left with canes that are at least pencil wide. Some factors that should go into choosing which canes to remove include age (remove particularly weathered canes, as their useful lifespan is 3-4 years) and health, proximity to other canes (you want the bowl as spaced out as possible), and the particular shape that you want to train the bush to.
Finally, cut the remaining canes back by about a third to half, depending on
how severe you want to prune, of their
length, no shorter than about about knee high (I've seen 15-24" recommended).
Here, you can see me about to cut my Double Delight down in size, and in the
second picture you can see the end result with the bush left with two strong canes.
As I mentioned above, understand the principles and prune with thought, but don't go overboard and spend too much time. It is said to be a good practice, for example, to look for an outward facing eye and cut about 1/4 inch above it (to encourage new growth to be outward instead of crowding into the center) at a 45 degree angle (to keep moisture from accumulating on the cane). But I've also heard that studies have shown that just cutting back crudely to the height you want after removing dead wood and canes you don't want gives the same results.
Your cuts should reveal good, clean wood, with a white or greenish color, not brown. You may need to cut back further if you see brownish wood, indicating cane dieback. Apply wood glue to the cane ends to help protect them from borers that may eat into the soft exposed flesh. Remember to replace the mulch when you're done.
In sum, sterilize your shears, remove any dead wood and suckers, open up the center, and pick, depending on the severity and shape of pruning you want, 3-6 canes (if you have them to choose from, less otherwise) to form into a bowl shape, and remove the rest. Trim back the remaining canes (20%-50%, depending on your preference); if you want to do it the recommended way, make your cuts at a 45 degree angle and about a quarter inch above swelling eyes that are pointing outward, in the direction you want to encourage new growth. These final pruning cuts should also reflect the shape that you want to encourage. End by applying wood glue to the ends of the canes.
Floribunda roses, sometimes called "cluster-flowered", produce medium-sized flowers in clusters or sprays (typically of 3-7 and sometimes more), as opposed to having a single large flower at the end of a long stem, as hybrid teas usually do. Introduced in 1930 as "Hybrid Polyanthas" as a cross between hybrid tea and the compact polyantha classes of roses, floribundas (so renamed in 1952) tend to be more hardy than hybrid teas and tend to be small or medium tall bushes.
Predating the formal introduction of the class, the first floribunda was 'Gruss an Aachen', bred in 1909. I've grown 'Pink Gruss an Aachen', 'Melody Parfumie', and 'Purple Tiger'; common floribundas include 'Europeana', 'Betty Boop', and 'Iceberg'.
Prune floribundas similarly to hybrid teas, with the same timing and basic techniques. You will want to prune less severely. Floribundas make excellent garden roses, so consider moderate or light pruning. Leave more canes, including in the center, and cut canes back maybe by 1/3. If you prune canes to different lengths, you will get more continuous blooming; let center canes be longer. Here, you can see my 'Melody Parfumie' bush before pruning, cleaning up of the center, (shortening of canes not shown), applying of glue to the cut cane ends, and the bush after pruning. You can see that my technique is to thin the bush out just so there aren't crossing or crowded canes, and to cut canes back by perhaps even less than a third, leaving canes of different heights.
I hope soon to add descriptions and pictures I already have for other varieties. Very quickly, here are some notes:
As I mentioned, it's great to get local advise from a rose society or horticulture expert. Any book about growing roses will discuss pruning.
On the internet ...