Winter Rose Care
Ann Marie Harris
ARS Master Rosarian, Reno Rose Society

Winter is a welcome season in our household. It used to mean no more bugs, no more mildew, no weeding, no watering, and absolutely no work in the garden. Since then, I have learned that not watering and not working are not good practices for our area. Now, winter means a few hours of work here and there to maximize gorgeous rose blooms and to minimize growing season problems. Heads up, winter is your opportunity to reduce the amount of work needed the rest of the year in your garden. For the best results, you need to understand where you are, what roses you have, and why you should care about winter care of roses.
To begin with, our region includes some areas that are in Zone 7 and, depending on elevation, goes down to Zone 5. The warmer areas are in Zone 7 and are in the lower elevations of the Reno-Sparks area and eastward into the Fallon area. As elevation increases, the severity of winter cold increases, going down to Zone 5 in the Lake Tahoe Basin. There is also a difference in precipitation, with the mountainous areas around Tahoe receiving several times more precipitation than even the Reno-Sparks area. Knowing this will help you take better care of your roses.
There many different classes of roses, ranging from the original species roses, from which all the later cultivated roses originated, to the classic hybrid tea. Some of these rose groups cannot be grown in our area without extra care and protection. Others will grow, but will not thrive without an extra bit of care. That is why it is important for you to know what roses you grow and their cold and drought tolerance. Most of the hybrid teas, floribundas, miniatures, classic shrubs, Austin shrubs, and large-flowered climbers are cold hardy and require little extra care other than watering. Most old garden roses are also cold hardy, but some classes are less hardy and certainly are totally not winter hardy in Zones 5-6. These include most bourbons, chinas, teas, noisettes, and some species roses.

Some of the winter hardy roses that need little to no winter protection include Altissimo, Crystalline, Dolly Parton, Elina, Fairy (polyantha), Gold Medal, Graham Thomas, Iceberg, Nevada, Olympiad, Peace, Pristine, Sally Holmes, Sheila's Perfume, Showbiz, Veterans' Honor, and nearly all miniatures. Some of the old garden roses that are hardy in our area include Austrian Copper, Harrison’s Yellow, Louis Odier, La Reine Victoria, Rosa gallica officinalis, and Tuscany Superb. Roses found to be less cold hardy here include Lady Banksia, Devonensis, Belle de Portugal, Mermaid, Royal Highness, and most teas (saying this after having killed off over 14 different ‘cold-hardy’ ones).
Key steps to taking care of your roses in winter are watering, limiting physical damage, minimizing pests and diseases, and providing winter protection. The results from taking a moment to evaluate your area and roses and spending a few hours doing winter care will save you time and expense in the long run.
Step one: for those of us on the eastern side of the Sierras, we live in a desert. That means unless you pay attention to the water your roses are getting during the winter, you could have dead or severely puny roses come spring. This may be why, early on, some of my roses dwindled away to nothing. Somehow the old wive’s tale here of needing to water lilacs in order to have lilacs bloom in the spring was not carried over to roses. If there has been no rainfall or snow in a two week period—water your lilacs and water your roses. Roses require four and a half gallons of water per week during summer, but one or two gallons every other week are sufficient in winter.
The second step is limiting the opportunity for physical damage from winds and snow load. Trimming back extremely long canes after the second hard frost, tying up long canes, and removing leaves lessen the opportunity for major cane breakage when the snow falls. In the Tahoe area, this could mean tying all the canes vertically together to lessen the chance that the snow will push the canes over.
The third step is minimizing pest and disease problems by cleaning up the garden and using dormant season sprays. A cleaned-up garden is a no-brainer: removing dead plant material can save you time and money. The old plant material provides an excellent hiding place for insect eggs, overwintering insects, and spores which in the spring multiply and cause bigger problems. Stripping the leaves also helps eliminate hiding places.
Dormant-season sprays can be the least toxic sprays you use on roses and provide the best return for your time and money. If you use these sprays, you will need to read the instructions on the containers and wear proper protective gear including gloves, respirator, spray suit, and shoes. If you have never handled pesticides before, you can always contact your local ARS Consulting Rosarians and the local County Extension Service for step-by-step advice. Be aware that although these materials are some of the least toxic you can use, you still need protection. Otherwise, at a minimum you will get chemical burns and major eye injuries. Spray on warmer days (it’s on the label!), do not spray on windy days, and cover the rosebush and the ground around the bush with the spray material.
Ideally, roses in northern Nevada should be sprayed at least twice while they are dormant. The minimum is spraying once in mid-December and then again just after pruning between the end of March and April 15. Most commonly used for the two-spray program is a dormant season horticulture oil mixed with a lime-sulfur solution containing 24-30 percent calcium polysulfide. Dexol’s Calsul Spray is a combination of lime-sulfur and oil that eliminates the mixing step.

If you cannot find a pre-mixed solution, you will have to make one yourself. Examples of locally available lime-sulfur solutions include Lilly-Miller Polysul Summer & Dormant Spray Concentrate, Ortho Dormant Disease Control, Orthorix Spray, and Cooke Sulfur Spray. You will mix one of these with a horticultural oil for best effect. A bonus for using lime-sulfur products is that the deer avoid anything sprayed with them.
The horticultural oils you can mix with the lime-sulfur solutions are 65-98 percent petroleum oil, which is formulated to be toxic to insects. These oils kill mostly by suffocating the insects and their eggs. Insects susceptible to these sprays include aphids, spider mites, scale insects, and mealybugs—all my favorite players. The oils also provide a protective coating over the buds which helps reduce later attacks by insects and fungus before spring. Locally available products include Ortho Volck Supreme Oil Spray and Volck Oil Spray.
For better results you can go to a three-spray program. Plan on spraying in early December, then again about 6 weeks later, and finally just after pruning. The first and last sprays should be the lime-sulfur mixed with horticultural oil and the second spray should be a copper sulfate (bordeaux) solution. I also use the same products on fruit trees and grape vines.
The last step you can take is providing winter protection. This involves a range of things from heeling over and burying the whole bush, to putting a structure & insulation over the bush, to adding 6-8" of mulch & 12-18" of branches, to simply adding a few inches of mulch over the bud unions, to doing nothing. The degree to which you winter protect will vary according to what you are willing to do, where you live, and what roses you grow. I used to drive in stakes, wrap burlap around, and backfill with insulation until I got to 350 roses. I still add some mulch or new soil over the bud union, but that is where I stop for all but a few roses. By the way, never just scrape up soil from around the rose bushes to use to cover the bud unions. You are ripping up the rose’s feeder roots. Today, if I really have to have that extra tender rose, it either goes in a pot that comes indoors for winter or it is planted under the eaves along the warmer sides of the house. Lady Banksia has survived this way for ten years; and Mermaid finally succumbed not to the cold, but lack of water. I do take time to protect new, smaller bushes with deeper compost or soil, covering sometimes the entire plant. If we are anticipated to have an extra hard cold snap, I will drag out the mesh cages I kept for a few of the miniatures and OGRs that I know are less hardy, put them around those roses and backfill with pine needles. Most years, I do not even have to do that. It really helps to keep records of what you have and how different roses have faired.
Part of your dormant season activities should also include checking your garden tools and supplies. Winter is a good time to send your pruners and saws out for sharpening and repair. You should check and see when you had your last tetanus shot. If your immunization is not current, you run a risk of getting tetanus from rose thorn punctures and other cuts you might get while gardening.

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