Prepping Roses for Winter

By Laurie B, Guilford County (NC) Extension Master Gardener

I always get melancholy when it comes time to prep my roses for winter. I think about all the joy my roses have given me throughout the season, the proliferation of color arrangements I created, and of course, the aroma released throughout the house. I do appreciate that there is a lengthy time period between the beginning of the rose winterization period and the last of the season roses, which helps wean me off my season. And because North Carolina has a longer growing season than other zones, one can enjoy roses all the way through to November. The process starts well before the first winter’s frost cloaks the rose bushes and prepares the plants for dormancy. Each year during the last week of August or the first week of September, around Labor Day, is a good marker date for the first winterizing steps to occur.

Winterizing is a process done to protect the roses for the next season’s growth. Hardy garden roses need less prep. Roses sold in this region are often hardy enough to sustain our North Carolina Triad region winters, however it is important when purchasing roses from out of state nurseries or from online stores to research their hardiness zone. Roses can be damaged by extreme cold freezes in this region. Canes can be damaged, broken, or worse, die off. The effects of damage to the plant, where the plant’s health was severely damaged during the previous winter, might not be recognized until the next season of hot, difficult weather conditions. A weakened rose might never reach its potential and will always have more difficulty fending off disease and pests, or it may suffer tissue damage with warmer temperatures. Picking the right rose for the area is a top consideration for its ability to survive through the winter, along with a good winterization procedure.

For my zone 7 roses I start off with placing Rose-Tone granular organic rose food on each rose. It includes an element called potash, where the name is derived from the harvest of potassium used to encourage water retention in plants, as well as disease resistance. Adding potash in the soil helps with the promotion of more abundant flowers next season and increases the plant’s health throughout the winter. It also offers a high ash content, which sets up the plants for winter. Sprinkle the granules around each plant out to the widest branch, then scratch the food into the top 1” of soil. For individual roses, use 1-1/4 cups of Rose-Tone per plant.

Rose-Tone is also a rose fertilizer and contains nitrogen, phosphorus, and potassium. This is the last time I fertilize my roses for the season. In early October, start to clean up around the roses to remove old mulch, fallen leaves and debris to avoid disease infection the following season. If the fall season is dry, make sure to water the roses well leading into the winter. This helps settle the soil and keeps the canes and roots in good shape, while making sure any elements or chemicals added have leached into the soil.

I also add gypsum to my winterization process, which is calcium sulfate, a naturally occurring mineral; this is especially good for breaking up the Triad Region’s compacted clay soil. You can also benefit from using gypsum for changing the texture of heavy traffic areas, compacted areas from flooding, or over-cropping. You will want to use a product with gypsum if you are expanding your rose garden for the next season or starting a new rose garden somewhere else in your yard.

I use mushroom compost around the roses after the older material has been removed, but you can also use a pine or hardwood mix. For zone 7 roses, cover the graft union with about 5-6” of pine, mushroom compost, or hardwood mulch. The base of tender rose bushes can be mounded or hilled with 10″ to 12″ of soil. This is particularly important if the rose is grafted. The bud union is the source of all new cane growth for these plants, and if it is damaged over winter, the plant may be lost. Also cover the center of the plant with fresh mulch.

The last step of the process is cutting back your roses after a few fall frosts have occurred, which is usually by the end of November or early part of December. It is important not to cut back your roses too early since they go through their own chemical process of becoming semi-dormant, critical for helping the plant to get through the winter months. Cut the roses down to help protect the canes from breakage due to ice accumulation or high winds. Prune only to 36” high while removing any damaged canes, branches, or leaves. Heavy pruning occurs in February. Read article on Pruning your Roses, link below.

Doing these simple winterizing steps will help prepare your roses for surviving and thriving the following season. The rest is up to Mother Nature and Jack Frost. If you are lucky, you won’t have any rose loss, but if we have a few deep freezes you can expect a few roses not to make it through the winter. I have been known to cover my roses during big ice storms with a few blankets. I really can’t promise that this strategy will always keep you from losing them during a strong freeze, but if you love roses as much as I do, blanket coverage is worth the time.

References

http://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/using-potash-in-garden.htm

Research on Mushroom Compost:

http://extension.oregonstate.edu/gardening/mushroom-compost-use-carefully

Link to Read article on Pruning your Roses: http://content.ces.ncsu.edu/roses-for-north-carolina