Richard Bogren | 1/27/2017 3:59:07 PM
By Dan Gill
LSU AgCenter Horticulturist
(01/27/17) It would be hard to dispute that the most popular summer-flowering shrub is the rose. Most roses need at least some annual pruning to maintain an attractive shape, remove dead wood and encourage vigorous growth and blooming. This is generally done from the last week of January in south Louisiana through mid-February in north Louisiana.
Pruning back roses takes some getting used to. Many new gardeners have a hard time getting up the nerve to cut their bushes back. If you don’t, however, the result will be tall, rangy, overgrown bushes that will not be nearly as attractive. It is far easier for you and healthier for the rose bush if you do this pruning regularly. Don’t forget that we also do a second, but not as severe, pruning in late summer around late August.
Hybrid tea and grandiflora roses
Use sharp bypass type hand pruners, which make clean cuts and minimize damage to the stems. Wear a sturdy pair of leather gloves and long sleeves because no matter how careful you are, thorny roses can painfully puncture or scratch your hands and arms. Should you need to cut canes larger than one-half inch in diameter, you should use loppers.
First, prune out all diseased or dead canes, cutting them back to their point of origin. Weak, spindly canes the diameter of a pencil or less should also be removed the same way. A good rose bush should have four to eight strong healthy canes the diameter of your finger or larger after this first step.
Cut back the remaining canes to about 24 inches from ground level. Newly purchased roses have already been pruned, and no further pruning is required. When you prune back a cane, make the cut about one-quarter inch above a dormant bud or newly sprouted side shoot. Try to cut back to buds that face outward, away from the center of the bush. The new shoot produced by the bud will grow that direction, opening up the bush for light, air and orderly growth. This may seem picky, but this really does make a difference.
Pruning other types of roses
Old garden roses that are repeat-flowering, landscape roses such as the popular Knock Out roses, floribunda roses and polyantha roses may also be pruned now. These roses, in general, have more pleasing shapes without severe pruning. They are only lightly shaped under most circumstances unless there is a need to control their size.
You should still check for any dead wood and prune that out. Excessively long, vigorous shoots growing out of the bush should be headed back to within the edges of the plant to keep the shape attractive. Other than that, how far back you cut old garden roses depends on the situation, vigor of the bush and the desired size. It is typical to cut back old garden roses and landscape roses by about a third of their height.
Any roses that are once-flowering, including many climbing and rambling roses, such as Lady Banks, Dorothy Perkins and Blaze and some old garden varieties, should not be pruned now. These roses produce their flowers in one big flush during late spring and early summer on growth made the previous year and then bear few or no flowers the rest of the year.
If pruned back hard now, they will produce few, if any, flowers. If extensive pruning is necessary, it is best done in midsummer after they have finished flowering. In addition, these types of roses should not be pruned back hard each year like modern bush roses. Pruning climbers and ramblers is largely determined by how large and on what structure they are being trained. Pruning, when done, is more selective and less extensive.
Most nurseries already have rose bushes in stock, and now through March is a good time to plant. If you intend to plant bare-root roses, get them planted before the end of February. Bare-root rose bushes should be planted before they begin to sprout.
Early planting allows rose bushes to become established before they begin to bloom. This increases the number and quality of flowers, and the bush is better prepared to deal with summer heat when it arrives in May. Plant roses in a sunny, well-prepared bed that has excellent drainage. For more information on growing roses in Louisiana, the LSU AgCenter offers an informative booklet, which is available free at your local LSU AgCenter parish office or online at http://bit.ly/2hX2KMZ.
On the move
Now is also a good time to transplant roses from one location to another in the landscape. Cool weather reduces the stress of transplant shock brought on by root damage when the plant is moved and increases your chances of success.
Care must be taken to disturb the root system as little as possible when moving roses. Dig plants with a ball of soil around their root system, getting as many of the roots as possible. If the soil falls away, do not let the roots dry out. Moisten the roots and wrap them in plastic, a garbage bag or damp fabric, then get the plants to their new location and plant them immediately. Make sure you plant them in their new location at their original growing depth, and water them thoroughly after planting to settle the plant in. Be sure to water regularly over the next few weeks and then during any dry periods over the next few months.
For harvesting roses or pruning old canes, bypass pruners work best. (Photo by Mark Claesgens)