A gardener in central Kentucky (zone 6) had aphids on Dr. Van Fleet and Knockout roses, and black spot on Glamis Castle. They picked aphids daily, wondered about pruning the diseased bush, and asked about deadheading Knockouts.
Daily picking leaves survivors. A strong hose spray knocks all aphids off; they can't climb back and birds eat them. This is faster and more effective than hand-picking.
Never prune a bush because of black spot—it needs all its leaves to fight the disease. Use a rose fungicide for black spot. Weird weather triggers outbreaks that aren't the gardener's fault.
Knockouts bloom prolifically with or without deadheading. It's optional; you likely won't notice a difference.
Identifying and Treating Scale Insects on Roses and Evergreens
15-Year-Old Roses Not Blooming in Partial Shade: Too Little Sun
Overwintering Large Numbers of Potted Roses: Garage Dormancy vs. Greenhouse Growth
Old Established Roses Not Blooming After Soil Disturbance
Fertilizing New Mini Roses: Why High-Phosphorus Fertilizer Burns in Winter
Carpet Rose Troubles: Pruning and Fertilizer Effects
Mystery Roses in Atlanta: Likely Climbers—Consult a Rose Specialist
Post-Storm Knock Out Roses: Mulch Fungus, Transplant Shock & Recovery
Transplanting Knock Out Roses in Zone 5: Fall vs. Spring Timing
Winter Protection for Young 'Double Delight' Roses in Ohio: Skip the Mason Jar
Pruning Knock Out Roses in Georgia: Annual Hard Cutback Works
Natural Aphid Control on Roses: Pet-Safe Methods for Bay Area Gardens
Indoor Mini Roses: Aphids, Fungus Gnats, and the Humidity Fix
Moving Gift Miniature Roses Outdoors in Western New York: Timing and Care for Zone 5
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