Black Spot on Roses
I am teaching myself how to garden, and have made to many mistakes. I have a small flower bed and an assortment of plants in it, one being an overgrown rose bush. (4 years old now - and struggling). She's tall - going on about 6 feet - I had not been pruning her back and just recently learned that this is a bad thing. Last year, she had a little bit of black spot, but was mostly ok. She attracts ants too, who like to nibble on her petals. She's a very sweet smelling flower, old fashion type - about 7 or 8 petals that start out as an orange color and turn yellow/with light orange accents as they open. The roses smell like oranges, more than roses. I wish I knew what type she was. I hadn't saved the info sheet when I bought her. This year, spring started EARLY, technically zone 5 or 6. boston, MA - area. Lots of rain and as of two weeks ago, she's in full bloom but her leaves are almost all falling off. Horrible case of black spot. Can't even touch her flowers without them breaking apart, too. Is there any hope to save her? I've been reading that there's fungicide sprays. Or should I be considering to just do a full pruning now, in the hope that there's still enough life in her that she'll rebuild her leave base and bloom again this season? In past years, she's a constant bloomer - from summer through November. Any advice on how I can save her?
Black spot can be a mean and nasty fungus to deal with I know. There is a product called Mancozeb that is available at a website called http://www.rosemania.com . It is truly the best I have found at stopping black spot in its tracks! It does leave a yellowish powdery residue on the foliage and canes but that is part of how it works. You can mix it and a fungicide calle Immunox together in the same spray tank just like you were adding only one of them. This will lessen the yellowish powder residue. However in a severe case I would probably spray the rosebush at least once with just the Mancozeb. Spray the rosebush at 5 to 7 day intervals for three to four spraying cycles. The foliage that comes back should be black spot free. Any older foliage that has black spot on it will continue to have the black spots, as once they are there they stay even after the fungus itself is dead. After the sprayings with the mancozeb, keep the bush sprayed with a fungicide called Honor Guard which is also available at the Rosemania website at approximately 10 day intervals. Especially when the climatic conditions are favorable for it to get going, such as damp days and rain. Spray as soon as you have a clear day to do so. I would only prune off the dead blooms and then wait for the sprayings to work and the foliage will return.
You can go to a website called http://www.helpmefind.com and do a search based on color and I believe they have an advanced search that will allow you to search by the fragrance too. This site is great and should help you find out the name of the rosebush.