Spring Rose Care - Spraying
On roses that have been troubled by fungus diseases a spray of lime sulphur during spring rose care will kill the over-wintered spores of blackspot and mildew. Mixing the lime sulphur with horticultural oil will control a broader range of pests. To achieve full effectiveness from the oil, this spray must be applied on a day when it is not going to freeze the following night. Spray the roses to the dripping point and spray all the surrounding mulch. This spray must be applied when the roses are still dormant—before they start to leaf out. During the next few days, top dress with enough mulch so that total coverage is 2 to 2 ½ inches. As roses leaf out, occasionally they are troubled by green aphids on the tips. These are easily controlled with insecticidal soap.