Cold-tolerant Knockout Rose shrubs are typically winter hardy to USDA hardiness zone 5. With a few extra steps, you may be able to protect your roses in even cooler climates.
Even so, keeping them safe, healthy, and happy through the winter months can be a bit challenging.
In this article, we share tips to help you protect your Knockout Rose bushes and trees in the landscape or overwintered indoors. Read on to learn more.
Winter Tips For Knockout Rose Bushes Planted in the Landscape
- Mulch before the weather turns too cold. Add a two or three-inch layer of pine or fir boughs, leaves, or garden mulch around your roses before the first freeze. This helps hold the warmth of the soil and protect the plants’ roots.
- Just before the first frost, wrap your rose bushes in burlap to protect them from harsh, cold, dry winds.
- Allow snow to build up around your mulched and wrapped rose bushes. Surprisingly, a thick blanket of snow acts as further insulations.
- After the last frost, when temperatures have stabilized in spring, remove the burlap and the mulch. Prune away any limbs damaged during the winter.
Winter Tips For Knockout Rose Trees Planted in the Landscape
- In freezing climates (down to 10° degrees Fahrenheit), you must wrap tree roses in a sturdy insulating material. Commercially available wraps are a good choice. Add a two or three-inch layer of mulch around the roots for further protection.
- In areas where the temperature drops below 10° degrees Fahrenheit, you will need to dig up your rose trees in late autumn and then lay them down to bury them in a trench throughout the winter. The trees should be buried entirely, at least one foot deep. A thick mulch of leaves over the trench is also helpful.
More on: Knockout Roses Cold Hardiness
- In the springtime, after all the danger of frost has passed, uncover/unearth your Knockout Rose trees. Prune away any dead or damaged limbs.
Overwintering Tips For Knockout Roses Planted in Containers
- Allow your container roses to stay outdoors during the first few cold snaps, but bring them in before the first hard freeze.
- Place the container roses in your basement, garage, or similar area that stays cool and dark (but does not freeze) through the winter.
- Check on your dormant plants at least once a month throughout the winter. Never let the soil in the containers become completely dry, but don’t overwater. Just provide a little drink as needed to keep your rose bushes alive through the winter.
- After all danger of frost has passed in the springtime, begin gradually transitioning your roses to the outdoors.
How Tough Are Knockout Roses?
These plants were specially bred for toughness by Bill Radler, Wisconsin’s Boerner Botanical Gardens director. They are disease resistant, cold, and heat hardy.
Many gardeners report having purchased some of these roses’ earliest incarnations and have kept them successfully for over a decade with little or no protection from the elements.
Your Knockout Roses’ hardiness in your setting will depend a great deal upon the care you provide. If you live in a very cold area, be sure to choose a sheltered location that gets excellent drainage and ample sunlight.
Throughout the growing season, provide your Knockout plants with proper rose fertilizer and water. When the cold weather comes, be prompt and diligent about mulching and covering to provide adequate protection from the elements.
In the springtime, rescue your roses from their winter slumber as soon as is practical. Be sure to prune and thin the plants properly to prevent crowding and rot and to encourage healthy new growth.