JoAnne Skelly
Rose pruning time is upon us. We generally recommend pruning roses around April 15. This timing is based on the fact that there shouldn’t be long term freezes anymore. Yes, there will be freezing temperatures periodically, but not for weeks at a time.
This may vary by microclimate with some areas more likely to freeze harder than others. Microclimates can even fluctuate on one piece of property, such as the north side being colder than the south side.
The reason this is important is that pruning encourages new growth, and new growth is very susceptible to freeze damage. This stress can set a bush’s vigor back and make for a weaker plant.
Not only that, but the damaged tissue is also prone to the development of canker disease below the pruning cut. Then, in removing the infected stems there may be nothing left to grow.
Pruning can make a bush look better, but it also encourages a healthy plant with more blooms. Eliminate damaged, dead or crossing stems. Roses three years or younger need little pruning.
Roses are disease prone, so sharp disinfected tools are necessary. Dull tools damage rose stems, creating wounds that invite disease organisms. Tools that haven’t been disinfected with something like alcohol also transmit disease.
Disinfect between cuts, not only on a single rose, but also across multiple roses. Bypass shears and loppers make clean cuts rather than smashing the stem as anvil shears sometimes do. A smashed stem is another invite to disease.
A pruning saw is a good tool for heavy old stems. Rose canes should be sealed after pruning with white school glue to prevent rose cane borers from destroying the stem. Just dab a tiny bit of glue on the cut end.
Make cuts ¼ inch above an outward facing bud. The direction the bud is going will be the direction of growth. The Utah Rose Society recommends removing “about one-third of the overall height or one foot lower than desired ultimate height” (utahrosesociety.com/rose-pruning/).
Remove and throw away all old canes, stems, leaves, etc., to eliminate sources of disease. Don’t compost rose materials. Before following rose-pruning advice, check what part of country the information is written for.
Too often, it comes from areas where there are moist, humid winters and roses don't dry out. Their skies may be dreary for months, sheltering plants from the sun. Here, we generally have sun and wind with little moisture.
Rose canes and crowns often die back in the face of drought and desiccating winds. There are many types of roses, which require different pruning techniques for optimum bloom. Check out the Utah Rose Society site for specifics.
A correction: after my last article, my friend Peg asked that I say she likes messing around with watercolors and that she is not a watercolor artist.
JoAnne Skelly is Associate Professor & Extension Educator Emerita University of Nevada Cooperative Extension. Email skellyj@unr.edu.