When did you spray the fungicide?

New Dawn *is* very disease resistant, and rust *is* quite rare here. The only time I've seen it was on a rose that had just been shipped from CA. I stripped the leaves, and haven't seen it since.

I would consider the rust a flukey case. Just keep the area fallen leaf free, and wait and see. There is the possibility the rust is coming from a non-rose diseased plant nearby, maybe an evergreen, needle or broadleaf, who is hiding the rust very well, having rust, but not overly impacted by it. Rhododendrons and Azaleas are often fungus traps, but grow satisfactorily anyway.

Moses

I sprayed the fungicide during the summer and into the fall - I first noticed it in August. I stopped as winter approached but just noticed this. The only other plants in this bed are hydrangeas and they seem fine. The neighbor has lots of evergreens and maybe it is coming from that. I will bundle up and pluck all the leaves then start spraying in spring when it wakes up. Fingers crossed it is a one off incident! Thank you so much for your advice!

Rusts are host specific. So rose rust is not the same thing as hollyhock rust, or evergreen rusts.

Be careful about when you spray. High temperature limits are easy to find. Low temperature limits can be impossible to find, but exist. Don't spray if the forecast is for a low below 40F. The results of a freeze on freshly sprayed plants is very similar to the black spots in your photographs. This is bad. Trust me.

If you are spraying for rust, use a fungicide for rust. Many aren't.

If it is one plants, look into what is different about that one. Is it in more shade? Is it in a wetter or drier place in the garden? That may help solve the problem.

Thank you @mad_gallica for the info! I can’t exactly remember when I last sprayed… it could very well have been when nighttime temps were in the 40s. There is another new dawn that I planted at the same time in a sunnier and drier spot and it has the same problem. I will research some rust specific fungicides and do my best to spray in the spring and summer when not too cold. Fingers crossed as I so love these roses

When in the growing season did they the fungi start? Be specific about both black spot and rust. Did the foliage drop in spite of your spraying? How often did you spray and what spray did you use? Can you provide season long bush shots?

Moses

Hi Moses!
I noticed the rust in August and we had a very weird summer with tremendous heat punctuated with huge rainstorms every week or so dropping 1-2”. I just used a Bonine fungicide that I had and sprayed maybe 3x since discovery (twice in summer and once in fall) and probably not enough. I’ve since read that they should be sprayed when leafing out. The leaves didn’t really fall but the rust did keep spreading and are on nearly all the leaves of both plants even though it is mid January now! Here is a photo from Sept - it was still quite leafy and green then but will orange spots. I noticed the black spots only recently and am not sure if its actual black spot or just the rust turning black

I would give them A spray with horticultural oil come early spring. This will encourage leaf drop of the disease leaves and help with Spread of rust for nexus season. I have multiple new dawn and have never seen rust on it

Hello everyone! After clearing all the fallen leaves on my infected roses in the winter, mulching to cover any spores on the ground and spraying copper fungicide every week for over a month the rust is back on all 4 of my new dawn roses. I just noticed it today and have been plucking the leaves. I am thinking I need to try a new fungicide and was hoping to get suggestions? Has anyone tried bonide mancozeb? Any other tips would be appreciated! I just love these roses but if they are going to be riddled with disease I think I am have to get rid of at least a few of them as I can’t manage the upkeep!