Protecting Cold-Climate Roses After Bacterial Loss and Black Spot

Dormant Oil + Sulfur: The Gold Standard

For Winnipeg Parks (lost to bacterial infection) and Morden Sunrise (black spot) in a cold zone:

• Apply dormant oil + sulfur spray twice, one month apart, before bud break.
• Winnipeg Parks and Sunrise are disease-prone; monitor closely and spray every 2 weeks if needed.
• Replant Winnipeg Parks in a hole amended with a bag of fresh potting soil to avoid soil-borne issues.

Better Long-Term Choices

Explorer Series roses (e.g., 'John Cabot', 'William Baffin') have superior disease resistance and cold hardiness. Many Old Garden Roses also thrive in extreme cold.

When to Replace

If a variety demands constant spraying, remove it. A 3-year trial is fair—then compost it.