The information in this week's article comes right out of a newsletter published by the Northeast Georgia Rose Society. The author of this specific section of the newsletter is Paul Blankenship, a consulting rosarian for the society.
Mid-February to early March is the best time for rose pruning. This gives you time to get the right tools for the job or sharpen those you may already own. A good pair of sharp pruners will make the job much easier. Will roses bloom without pruning? Certainly. Will roses be as healthy and productive if left unpruned? Certainly not!
Here's how to get the job done. First, remove all dead and diseased wood. If this means removing a cane at the band union (base) of the plant, use a small pruning saw to remove the cane cleanly, leaving no stub. Next, if the rose blooms only once a year, such as Climbing Queen Elizabeth and Lady Banks Rose, stop pruning and go to the next plant. These once-a-year bloomers flower on old wood; any wood you remove now will only decrease potential bloom you will enjoy this spring. Many climbers, ramblers and Old Garden Roses fall into this category. After the spring bloom you may return to these plants and shorten their canes by 1/3 and then remove any canes which do not fit the space allotted. On plants which flower repeatedly through the season such as most of the other roses we grow, you may go ahead and prune severely.
Contrary to what you may have heard, pruning is not an exact science. Proof of this theory is quickly supplied by talking to three or four experienced rose growers about the subject. Each will prune somewhat differently, but consistently. The key point is to remove all dead and diseased wood, and reduce the remaining canes by at least 1/3.
As you prune, it is important to position the shears so that the cutting (sharp) blade is below the stationary blade. Even sharp bypass pruners will injure the portion of the cane which come in contact with the stationary blade. Make a few trial whacks and examine the wood on either side of the cut. One side of the cut will show a small tear on the bark. The other side will be cleanly cut. This will help you see which way to hold the pruners.
As you cut take note of the appearance of the center (pith) of each cane. If the pith is brown or black, continue to cut the cane lower until green or white pith is found. In some cases this may mean a drastic reduction of the cane. Occasionally, the pith will become darker and darker with each successive cut and the cane will have to be removed at the bud union. Remember, it's the inside appearance of the cane and not the outside appearance that determines whether the cane is a keeper or not.
Why is the pith so important? The pith transports moisture and nutrients upward to the leaves where it will be transformed into food. Yum, yum for the rose! Removal of damaged canes will stimulate the rose to produce new canes which will be much more efficient in carrying out this important function.
Want to go a little deeper into the subject? I was hoping you would say OK! The rest of this material is desirable but not required. It would be best at this point to examine the configuration and number of the remaining canes on our imaginary hybrid tea. If there are any canes which cross through the center of the plant or grow inward, it would be best to remove them. We are striving for a configuration where canes grow up and out from the bud union leaving the center of the plant open for good air circulation. Further, if there are more than five or six canes present, remove the oldest, least productive canes until the five or six strongest, youngest remain.
Now we come to the real controversial part. Most good growers go beyond removing 1/3 of the cane as I mentioned earlier. How much beyond? Well, that depends on who you ask! Folks who are after garden display will usually prune higher, say three feet, so that more bud eyes are left on the plant. More bud eyes mean more shoots which will ultimately result in more buds and more blooms. Exhibitors or those who prefer fewer but larger blooms will prune much lower, say about 18 inches. This is not crucial, and I will dwell on it no further! At whatever point you decide to make your cut, please make that cut about 1/4 inch above an outside-facing bud eye. That is, bud eye which is looking away from the center of the plant. Growth which emerges from such an eye will grow outward and help keep the center of the plant open, again for good air circulation. Having good air circulation will help control the dreaded enemy - blackspot.
A final point. Get off the wallet and buy a quality pair of bypass (not anvil) pruners. Sure, it is going to set you back at least $25. But, man, oh man, after you have pruned a dozen or so bushes, a good pair of pruners pays for itself in reduced effort and nice clean cuts.