Q&As/Rose Plant Diseases/Spraying Roses
Please can you outline a spraying schedule for roses. I live in town and get rust and black spot every year. Each year I’ve used Shield and Super Shield and still the leaves look awful. Do I need to look at a winter clean up?
Firstly, straight after your winter pruning is completed, apply a very thorough clean-up spray of horticulture oil such as Conqueror Oil and an application of Copper compound such as Copper Oxychloride. Garden hygiene is very important with roses so remove any dead leaves or diseased wood from the ground. Don’t put them in the compost bin - remove them from the property as they can harbor overwintering fungal diseases and re-infect your plants come spring.
If roses get stressed they are more prone to attacks from diseases. Healthy roses that are cared for through good nutrient management, watering and mulching means less need for spraying. It is very important to use a Rose fertiliser such as Daltons Premium Rose & Flower Fertiliser as the nutrients are designed especially for roses and provide good bloom strength, colour and vigour. Feed with fertiliser in mid-October and repeat every 4-6 weeks through to Christmas. Avoid feeding in the height of summer when plants are struggling with the heat. Recommence feeding again in early March through to mid-April.
If you do need to spray, Shield should work, but it may be the timing of the application that is the issue. When the first bloom is completed, which is around late November/early December (variety dependant), commence spraying at 3-4 weekly intervals with Shield. You also need to consider the weather, so re-apply after rainfall as it will wash off the protection– this can mean spraying several days apart. To help reduce black spot and rust, maintain your roses in good physical condition throughout the summer months. Give them a deep watering every two weeks at ground level and regularly apply good quality mulch such as Daltons Mulch & Grow. Avoid getting foliage wet as encourages disease.
Top tip: If your roses continue to suffer with disease then it might pay to look for new or disease resistant varieties.