Like every other aspect of caring for the Knockout rose winter care is simple and straightforward.
The Knock Out rose introduced by Will Radler in 1989 is very hardy in mild climates. However, disease resistant Knock out roses do require some special care in areas that experience very cold temperatures and/or high winds in the winter.
In USDA zones 5b-11, winter protection of Knock Out roses is very simple, indeed. A bit more caution and preparation are needed in zone 5a.
Steps For Winterizing Knock Out Roses in Zones 5b-11
- Prepare your Knock Out rose bush in advance of the first frost by raking the ground clear around each of the roses in your garden. Do a light pruning to tidy up unruly canes or branches.
- Provide your Knock Out roses with a fungicide treatment. In cooler climates (e.g. 5a) use a powdered product. In warmer, drier areas you can use a light treatment of liquid fungicide.
- Mulch around each of the Knock Out rose plants in your garden to help keep the soil temperature consistent. Two or three inches of good quality mulch is advised. Be careful not to let the mulch touch the plant as this will encourage rotting.
- As spring approaches, begin to prune. You want to perform your spring pruning while your roses are still dormant.
Your late winter/early spring pruning should be fairly aggressive. This is when you remove damaged limbs, cut out dead wood and remove interior stems for better air circulation.
This is also an excellent time to shape your rose bushes as you will have a clear view of the “skeleton” of each plant.
Learn more about Pruning Knock Out Roses
Special Winter Protection Instructions For Zone 5a
Rake and prune your bushes as in steps 1 and 2 above. Have some plastic foam rose cones on hand to protect your roses against both cold and high winds.
After you have done your initial trimming, try fitting the cones over your bushes. If they don’t fit, more pruning is necessary.
Once you have your bushes properly trimmed to be fitted with rose cones, you can apply a fungicide. In zone 5a, you must use a powdered product because liquid products tend to freeze.
After applying fungicide powder to all of your plants, shape the soil at the base of each plant into a sloping mound. It should be eight or ten inches high and should make contact with the lower stems of the bushes.
With trimming done, fungicide treatment complete and soil in place, you can fit your cones to each bush.
Next, mulch around the bushes with leaves or straw. You should add several inches of mulch to each of your soil mounds. This will provide extra insulation and protection against cold.
Remember that wildlife gets hungry in the wintertime. If there are deer in your neighborhood, you may want to take the added step of covering the tops your shrubs with burlap sacks. This will prevent deer from nibbling during lean and hungry times.
If you don’t have plastic foam rose cones, there is an alternative. Just wrap a length of rope around each shrub very lightly. You’ll want to work your way from the bottom of the bush to the top. The purpose of this is to prevent individual limbs from being broken by high winds.
This method doesn’t provide shrub protection against cold.
If you are using the rope method to defend against wind, you will definitely want to add some other sort of protection against cold (e.g. extra straw or foliage and a burlap bag).
Once your roses are covered for the winter, you shouldn’t need to do much to them. Make sure they are well watered in advance of the first freeze.
After the first freeze, they will go dormant for the winter and will not need much care until spring.
Taking these steps you can look forward to preparing your hardy Knock Out rose for the upcoming blooming season of flowers. More on flowering with When do Knock Out Roses bloom?