Do you have any idea what cultivars they are? What their names are? How old they might be? Are photos possible? There are, to be honest, some roses I wouldn't plant (climbers, in PARTICULAR) because they are not resistant to our common fungal disease, and would have to be sprayed regularly to remain free of disease. Can the trees be pruned some -- to allow more light through? It sounds as though you have made them healthier. Now it remains to see what you can do with their environment. You don't REALLY need a full 8 hours of sun -- but they will need SOME sun. So if making the tree canopy more open is possible, that could do the trick. Likewise, you may find that NOTHING helps, and they require spraying. Spraying giant climbers is not on my list of Good Things To Do. In fact, if that were the case, I would remove them. Jeri

The 2-in-1 granules do not contain a fungicide. They are cheap fertilizer mixed with the most toxic of all home garden pesticides, Di-syston (disulfoton). IMO (and I use lots of synthetic chemicals), this material is too dangerous for home garden use, and it will do your plants no good (compared to cheap 10-10-10 granular fertilizer). The All-in-One drench product does have a fungicide that should control mildew on phlox, along with more cheap fertilizer and an unnecessary and possibly harmful insecticide. There are all sorts of cheaper, safer solutions for powdery mildew. The chemical companies market these combo products to novice gardeners who don't know how to diagnose problems. Experienced gardeners avoid combo products and advise against buying them.

I've grown Jeanne La Joie for years and years and never had a powdery mildew problem with her. Blackspot definitely just not PM. Since PM is a definite problem on some of my roses I know that it's not just my climate. I suspect that the difference may be location. Jeanne La Joie is located along a fence in a windy site where air circulation is no problem. Also "dry feet" on a rose can help contribute to PM, so always make sure that your roses are well watered. As to picking off each and every leaf of roses prone to PM it sounds good, but most of us have a life. Your best offense is a good defense. For PM the Triflorene found in Ortho's Fungunex (sold now as Ortho's Rose Pride) gives very good protection against PM. But you must have it in place as soon as conditions are ripe and even before the leaves have fully leafed out. As soon as the day time temperature hits 68-70 degrees in spring start spraying per label instructions. Fungunex is also good for preventing blackspot if you have that. You might want to add a layer of bark mulch in early spring under the roses to cover up any leaves which may have fallen during winter and are harboring disease. Once PM strikes there really isn't any effective way to cure it. Preventative spraying will not return the affected leaves back to looking good, but will prevent new infection. Now you can spray with any material you like. But if it isn't doing the job then what's the point. I used the Cornell forumla years before and it not only wasn't effective on some of my roses, it actually harmed others. But then we have a long growing season with lots of time for disease to take hold....As for Thrips, I've found nothing effective against them that I didn't consider too toxic. They are cyclical, so some years are worse then others. Personally I've gotten rid of those roses that suffered severe Thrips damage every year and just live with the occasional damage on my other roses.

Title: "Biological control of rose powdery mildew (Podosphaera pannosa (Wallr.: Fr.) de Bary" See: https://www.researchgate.net/profile/Vijay_Kumar646/publication/311499625_Biological_control_of_rose_powdery_mildew_Podosphaera_pannosa_Wallr_Fr_de_Bary/links/5aaa9f270f7e9b8826711df4/Biological-control-of-rose-powdery-mildew-Podosphaera-pannosa-Wallr-Fr-de-Bary.pdf