Roses have long been a landscape staple. Stately hybrid tea roses graced gardens for years. As styles and trends changed, these florist-type roses evolved to newer introductions. So-called easy care landscape roses now fill space in the garden, including the most popular variety, Knock Out.
As we head into winter, your roses may need some attention, depending on the type you grow.
Roses produced through grafting can be at risk during winter’s cold. Grafted roses, which include most hybrid tea, grandiflora and floribunda varieties, have a durable, no-name rootstock onto which the named variety has been attached. These plants usually have a knock or bulge at the graft union.
The graft union must be protected from extreme winter conditions, because if it dies, so does the rose. Mound 6 to 8 inches of soil over the crown of the plant to protect it. This cone of soil insulates the graft union from freezing and thawing. Once growth begins in early spring, the soil can be removed and the rose readied for another growing season.
Many of the roses being produced today are no longer grafted. That means the roots as well as the canes are all the same genetics or variety. If the plant winterkills, the roots are usually hardy and new canes develop from below ground to renew the plant. The majority of easy care landscape roses are produced in this method.
As you can see, there is an advantage to planting own-root roses, as they are much more dependable and require less maintenance. Own-root roses need no special protection during winter. Ideally, and as part of good gardening practices, a 2- to 3-inch layer of mulch would be around the planting bed.
Avoid fall pruning
There is a misconception that roses should be pruned in the fall, when in fact it is best done in mid-March through early April as new growth develops. Fall or winter pruning can result in additional injury from cold snaps. The area around the pruning cut does not seal over, and the wound can dry out, killing the cane. The result is a weakened plant come spring.
Wood that is damaged during winter will turn black. Weakened canes will also have dark red sunken lesions. When pruning time arrives, the first cuts to make on the bush are to remove all tissue that has been damaged by the winter cold. Once this wood is removed, it is much easier to make the final pruning cuts to shape and open the bush for good sunlight and flowering.
Give the rose a drink
Kansas City winters have been dry. Plants that have good soil moisture over winter are better prepared to withstand cold temperatures. Take advantage of milder winter days and soak the rose root system thoroughly.
Providing care now will help ensure that your plants shine come summer.
Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Got a question for him or other university extension experts? Email them to firstname.lastname@example.org or visit KCGardens.KansasCity.com