How can I protect my roses during winter in zones 4/5?Updated 12 days ago

In USDA Zone 4/5, winters can pose challenges for roses, particularly for hybrid teas, floribundas, and other less-hardy varieties. Proper winter care is essential to ensure the plants survive the harsh temperatures and emerge healthy in the spring. Whether your roses are outdoors or in an unheated hoop house, thoughtful preparation and insulation are key. 

Cold-hardy rose varieties, such as shrub roses or rugosas, are naturally better suited to Zones 4 and 5 and may require less intervention. If you're growing tender varieties or grafted varieties, extra care is especially important to prevent dieback. Additionally, snow cover can act as natural insulation, so if your hoop house or outdoor roses accumulate snow, it provides an extra buffer against extreme temperatures.

If a heated greenhouse or unheated hoop house are an option for you I would recommend those as my first choice. If budget or time are tight then leaving outdoors will work if you are prepared.

Outdoor Roses

For roses left outside, begin by cleaning up the plants in late fall (early October-now). Remove any dead or diseased leaves to reduce the risk of overwintering pests and diseases. While it's important to protect the plants from wind damage, avoid heavy pruning at this stage, as it can encourage new growth that may not survive the cold. Instead, trim back any particularly long canes to prevent them from whipping around in winter storms.

The most effective way to protect the crown and lower canes of your roses is by mounding soil or compost around the base of the plant. Build up a mound about 8–12 inches high, ensuring the crown is well-covered. Once the mound is in place, add a thick layer of mulch, such as shredded leaves, straw, or evergreen boughs, for additional insulation. This helps to keep the roots protected from fluctuating temperatures.

For extra cold-sensitive varieties, consider using rose cones or wrapping the plants with burlap. If you opt for this method, create a loose framework around the plant with stakes and wrap the burlap around the frame rather than directly against the canes. This ensures good airflow and reduces the risk of rot caused by trapped moisture. Avoid using plastic covers, as they tend to trap condensation and can lead to fungal problems. In the end you'll have a cylinder shape wrapped around the rose that looks like a stuffed rose burrito.

Lastly, make sure the roses are well-hydrated before the ground freezes. Deep watering in late fall helps the roots retain moisture through the winter months when they cannot take up water from frozen soil.

Roses in an Unheated Hoop House

An unheated hoop house can offer roses additional protection by reducing exposure to harsh winds and heavy snowfall. However, since it doesn't provide warmth beyond natural solar gain, extra measures are often necessary to keep the plants safe during prolonged freezing temperatures. I like options that are pre-made kits from Farmers Friend.

Begin by insulating the roots and crowns with a thick layer of mulch, similar to outdoor care. Inside the hoop house, additional insulation can be provided by covering the plants with frost blankets or agricultural fleece, particularly during extreme cold spells. If temperatures drop significantly, you might also consider using row covers or layering additional materials over the plants to create a microclimate with slightly more warmth.

It's important to monitor conditions inside the hoop house carefully. On sunny winter days, the interior temperature can rise quickly, so venting the structure during warm afternoons is crucial to prevent overheating or excess humidity. High humidity can encourage fungal issues, which are detrimental to semi-dormant roses.

Watering should also be monitored inside the hoop house. While roses won't require much water during their semi-dormant phase, you should ensure the soil doesn't completely dry out. Water sparingly as needed, taking care to avoid overwatering, which can lead to root rot.

By preparing your roses thoughtfully and providing adequate protection, you can minimize winter damage and set your plants up for a strong start in spring.