PART 1: I have a 70 yr old rose bush that bloomed from June through Sept. with fragrant roses. For the past few years, it blooms in June with very green leaves and lots of flowers. After that bloom, the leaves turn yellow with black spots and the roses do not open up. What is the problem? Thanks, Sandra
Answer
Hi Sandra,
Your rose bush has Black Spot, a fungal disease that affects roses. The fungus initially develops as small black spots on the leaves, eventually increasing in size causing the leaves to turn yellow and fall off. This fungus affects the overall health and vigor of the plant creating a stressed plant that will not flower and will not fight off the disease naturally. Also, since this is a 70 year old plant, it does not have the built-in disease resistance from the variety of fungi that are around these days, so Black Spot will be a problem. Keeping your plant healthy with proper pruning, watering and feeding will increase the vigor of the plant and will help it to naturally fight off disease and insects.
Black Spot can usually be helped by proper pruning of the shrub. All shrubs, especially roses need to be pruned and thinned in order for air to circulate through the plant and for sunlight to reach the center of the plant. The air circulation and the sunlight deter diseases like Black Spot from taking hold by preventing moist, warm, dark areas within the shrub for the fungus to grow. The hot, humid weather during the summer also encourages fungus to grow so that's why it is so important that the shrub is pruned properly.
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About Linda Lillie
Linda K. Lillie is the President of Sprigs & Twigs, Inc, the premier
landscape design and maintenance, tree care, lawn care, stonework, and carpentry
service provider in southeastern Connecticut since 1997. She is a graduate of
Connecticut College in Botany, a Connecticut Master Gardener and a national
award winning landscape designer for her landscape design and landscape installation work.
