Pruning Hybrid Tea Roses
Sharpen the pruning shears, all of January is pruning, and dormant spraying month.
If you are a neophyte pruner, or you need some reminders, there are classes held at almost every nursery on pruning techniques, as well as classes by rose clubs, and botanical gardens.
The hybrid teas are the easiest of the roses to prune. Their flowers bloom on new wood, meaning the stems that will grow this year, so pruning for new growth is the object of pruning a hybrid tea rose. A pair of heavy leather gauntlet gloves and a sharp bypass pruner are necessary to get the job done safely. An anvil type pruner is not effective for this job as it crushes the stems and causes too much damage. Strip off all of the leaves, even the new ones, and cut any roses still in bloom so you can see the basic structure of the plant before you cut. Remove any of the dead branches first. After this, a lot of subjective decision making begins. You want to open up the plant to good air flow so when it is in leaf and bloom diseases can be kept at bay, or at least easier to treat when they appear. You also want to direct growth to the outside of the plant where it can be seen, and where it does not have to compete for light and air in a dense mat of brambles growing through the center of the shrub. Depending on your belief, practice and courage, you can do a light, medium or hard pruning. I usually prune medium too hard. A light pruning would only be to remove a few heavy old canes, remove the leaves and prune back branch tips. This is what I would do for a newly planted, or small rose. If you are just not sure, standing before your rose with your knees knocking and your hands shaking, a light pruning is a start and better than none at all. There are actually not that many things that can really ruin a rose forever except for removing the grafted union of the root stock and the grafted rose stock. Most roses are not grown on their own roots, but rather are grafted to a hardier, more disease resistant rootstock. If the top gets cut off below the graft union, the roses that you will get will be that of the rootstock and not the expensive hybridized rose you thought you had. The graft union is easy to spot in most cases. It is a gnarly, burled part on the stem at the base of the rose stem. Suckers that arise from the area below the graft should be cut back. These are often more vigorous than the hybrid part and will steal away all of the nutrients and water if they aren't keep in check. A medium pruning will give you a rose with three to seven main canes cut back to 18" to 24". The main canes should radiate from the main bud union, the graft, towards the outside, leaving the center of the bush open. All dead, diseased and scraggly looking stems will be pruned away, and crossed or rubbing stems will be pruned out. When you prune a main cane, look for an outward growing bud, and cut just above it. I cut an inch or more above the bud to prevent damage to the bud. You can come back later and prune back further if needed. In the event of a freeze this little extra will sometimes take the freeze and spare the bud, it just provides a bit of insurance. Some rosarians will seal the canes once they are pruned to keep out borers. There is a problem around here with as you will find evidence of brown frass around hollow rose canes that have died back after the borer enters the pithy center of a pruned rose cane. They can hollow out a cane killing it as they munch their way down. A bit of shellac, or white glue to plug the hole will help keep the intruders out.
After you have pruned your roses, spray the plant and the ground below the plant with a dormant spray, combination dormant oil and lime sulfur. The dormant oil kills overwintering insect eggs by smothering them, and the lime sulfur will help to control dormant diseases, especially fungal diseases of which rust, powdery mildew and black spot are all part of. You can also use a copper-based spray or a Bordeaux spray, but wear protective clothing. Copper sulfate when mixed with hydrated lime makes the Bordeaux mixture which was one of the first fungicides used by gardeners, discovered accidentally in the Bordeaux region of France, and is still in use today. Copper sulfate is toxic to most plants and should be used only as directed. There are formulations on the market that make it less toxic to the plant when used properly, and it is a very effective fungicide. Refer to the label for the plants and diseases the product is registered for. Copper is toxic to fish and should not be used around ponds, or aquatic life. If you have the choice between limesulfer or copper, limesulfer is overall less toxic and gentler on the environment.
Climbing roses and heritage roses, bourbons, and rugosas need to be pruned differently, so don't use the hybrid tea approach to them, or you may have no blooms next year. No fertilizer at this time of year, that will come mid March to early April. Do shop for bare root roses this month. Save the rose hips and occasional bloom for indoor flower arrangements as you prune.
Carol de Maintenon is a member of Garden Writers of America and owner of Benicia Garden & Nursery.
