Anyone who has roses know they are susceptible to many diseases including powdery mildew, rust and black spot. The main problem I have in my garden is with black spot. Black spot is caused by the fungus Diplocarpon rosae. This disease will cause the plant to lose all of its leaves if left untreated. The spots can range in size from 1/16 of an inch to 1/2 inch. Surrounding the black spot will be a yellow circle and these leaves will eventually fall off the plant. You have to be very meticulous about cleaning up all these infected leaves from your garden. Otherwise the disease will keep on spreading. Black spot is caused by water remaining on the leaves of the rosebush for several hours before drying. Therefore, roses are more vulnerable when it’s raining. In addition, if you overhead water this can cause the same problem. I always water near the base of the plant so that the water is going to the roots. This disease can affect the rose canes as well as the flowers. To prevent this disease you need to do a thorough cleanup of your rose beds in the fall and cut back any parts of the cane that are affected as well. A fungicide schedule should be put in place preferably before the spots appear or at the first signs of infection during the summer months. This schedule will have to be followed through until the first frost in your area. Usually this will involve some spraying every 7-10 days. I try to stick to things that are friendly to the environment and I don’t want to spray anything that will harm my pets or family. Plus I also don’t want to harm the beneficial insects that frequent my garden daily. Fortunately, there are roses that are being introduced that are disease resistant such as the Knockout roses. I find these to be very easy to maintain. As you can see in the picture their foliage is very healthy and vigorous. They bloom for me prolifically from late April up until the first hard frost in the fall. The flowers are a single petal type like some of the old fashioned roses that probably grew in my great grandmother’s garden 80 years ago. Personally, I think the flowers are sweet and simple. The color changes as they age as well. They start off this true red and fade to a violet-pink shade. The blooms are usually in large clusters so they really make a statement when the entire plant is at it’s peak. In addition, you don’t have to deadhead these roses as meticulously, they will keep blooming whether you cut the old flowers off or not. I tend to deadhead the faded blooms because I like a tidy garden. These also make great foundation plants because they are almost maintenance free. Every spring I cut them back to about 12″-15″ from the ground and that is about all the maintenance they need. I don’t even give them any extra water like I do my hybrids. They seem to tolerate the heat, drought, full sun, part sun or whatever you can throw at them. Wonderful additions to any garden setting.
True friendship is like a rose: we don’t realize its beauty until it fades. – Evelyn Loeb