If you live in a colder climate and grow tender hybrid tea, grandiflora, or floribunda roses, you may want to provide them with some winter protection before the temperatures dip too low. Depending on your preference and your climate, you can choose from several methods:
- Hilling with soil or mulch.
- Building winterization structures.
- Using the “Minnesota Tip” method.
Do I Need to Winterize My Roses?
You may need to winterize your roses if:
- You live in USDA Hardiness Zones 5 and colder; or
- Your ground stays frozen solid for much of the winter, with temperatures staying below 20º F or regularly dipping below 10º without a heavy, insulating snow cover.
You probably don’t need to winterize if:
- You grow wild or native roses, or have chosen extra-hardy varieties designed for your climate.
- Your winter temperatures only occasionally drop into the single digits.
- You have very wet, rainy winters – in consistently wet weather, your roses are better left uncovered to prevent disease.
When to Winterize
Winter protection should be applied after temperatures are cold enough for several frosts, but before the ground freezes. You want your roses to be used to some cold temperatures before insulating them.
Preparation for Winter Protection
Follow these steps to prepare your roses for the winter:
- Make sure the plants are healthy, by addressing diseases and pests as they arise and keeping them watered and fed throughout the growing season.
- Stop applying nitrogen fertilizers by early fall. Some gardeners like to apply a winterizing (non-nitrogen) fertilizer in late fall.
- Remove all fallen leaves and debris from within and around the plant.
- Prune back canes to 30-36 inches. Don’t do your major pruning at this time, just prune enough to prevent breakage in strong winter winds. Also remove (and do not compost) any diseased or dead branches. If you have to make any major cuts, seal them with wax or white wood glue.
- Tie the tips of long canes together, to prevent breakage in the wind.
Now you’re ready to winterize!
Hilling with Soil
Soil conducts heat, so a nice mound of soil around your rose bush will conduct warmth from the ground up into the main stem.
Using a shovel, simply mound soil around the canes of your rose, making a mound about 1’ high by 1’ wide. With grafted roses, your mound should cover the bud union, which is where the main stem was grafted onto the root stock. The bud union is a noticeable bump on the stem, right near ground level.
If you use this method, be sure to bring in extra soil – don’t dig soil from around your roses, or you’ll expose the roots to the cold.
Then simply apply a nice layer of mulch, and you’re done!
Hilling with Mulch
If you prefer, you can use mulch instead of soil. While mulch doesn’t conduct heat like soil, it acts as an insulator that keeps the cold away. If you choose this method, make the mound at least 18” high and wide.
Using Winterizing Structures
If your roses are particularly tender, you may want to go a step further and use a winterizing structure that completely covers the plant. You can make your own structure by surrounding each plant with a cylinder of chicken wire supported by plant stakes.
- Begin by mounding soil over the crown of the plants, using the Hilling Method above.
- Install the structure. Your rose should have about a foot of clearance all the way around.
- Fill the rest of the structure with leaves, straw, or other loose and non-compacting material.
Winterizing structures have their drawbacks. To begin with, rodents find the insides of these structures quite cozy, and they may decide to spend the winter hibernating and feasting on your tender rose shoots. Also, if winter temperatures fluctuate wildly, the insides of the structures can heat up, become humid, and breed fungus and disease. Make sure there are holes in the top for air circulation.
You can also purchase winterizing structures for your roses rather than building them – cones, collars, and other structures are available to hold your insulating material. If you go this route, the cones made of foam are not recommended. During a warm spell, they can heat up considerably, causing the rose to break dormancy or breed disease.
Winterizing Climbing Roses
Tender climbing roses can be bundled and tied, then wrapped with straw and burlap. Use the hilling method around the roots and crown. Climbing roses can also be winterized using the “Minnesota Tip” method below.
All this needs is a Jack-O-Lantern head, and you’ll have a nice autumn scarecrow.
The “Minnesota Tip”
This method is not for the faint of heart, nor is it necessary unless your winters are extremely severe and you’re a fan of tender rose varieties. The “Minnesota Tip” involves digging a trench and carefully leaning over and burying your entire rose.
Winterizing Container-Grown and Tree Roses
Container and tree roses can also be tipped and buried, or they can be stored in a garage or unheated cellar where the temperatures will remain between 25º and 40º all winter.
When to Remove the Winterization
Remove the winterization in the spring, after the ground has thawed but before the rose has put out much new growth. Some gardeners remove the mulch covering in early April, then the rest of the soil around mid-April.
Winterizing roses takes quite a bit of work, but it allows gardeners in cold climates the luxury of a delicate, established rose garden.
- Winterizing Roses from Year Round Gardening Projects
- Winterizing Roses Using the “Minnesota Tip”
- Agriculture Canada’s List of Winter Hardy Roses