Many posters on this forum use Bayer's Garden Disease Control for Roses, Flowers, and Shrubs (don't confuse that with the other Bayer products which are combos--this is just fungicide). It is sold at Lowes or you can order it online.

Make sure you read the directions carefully and follow safety precautions.

Sorry on the liquid fertilizer--never use it. But I'm sure someone else will come along with a recommendation.

Kate

Miracle Grow sells a liquid fertilizer for roses. I've found that with my heavy clay soil, I need only a fraction of the fertilizer used by folks with quick draining sandy soil.

Spraying much better than a soil drench for BS--not only does the soil drench use a lot more pesticide, but the usual product contains insecticides that are usually best avoided. I've noted that if I spray during bright sunny weather, I need less fungicide than if I spray in the evening, when it is harder to see the spray on the leaves.

Use a copper spray or Bordeaux mixture. Neither is poisonous; Bordeaux mix is actually "permitted" in organic gardening ,at least here in Europe.
I don't know exactly how bad your b-spot situation is, but just because roses get it bad does NOT mean that they will die!!! Even if all the leaves drop off, it doesn't mean that they are dying. You can try spraying them and the ground around them with copper,then fertilizing them (if you use a granular one, water them thoroughly), and then mulch them. Keep in mind that if it's very hot the roses may simply need to rest,however... bart

I am no-spray and almost every year half my roses completely defoliate from blackspot. They all recover.

I am right there with you! My roses were doing very well, until about 2 weeks ago. Now, my once growing by leaps and bounds, Angel Face has very few leaves on it and my Fragrant Cloud to her right is covered with BS and dropping leaves as well. I had gotten the recommended Bayer but the manual pump broke. However, those I did spray prior to the "disfunction," Have cleared up quite a bit. I would give it a try...though it isn't organic. I tried organic at first too, with no success. :( Good luck!

We've had a rainier than normal summer here as well and a few of my plants have defoliated badly. I started off using a sulfur spray at the beginning, but switched to the Bayer Disease Control for Roses. Not the the 3 in 1 or the one with the fertilizer, just the fungicide. I just sprayed the day before last and yesterday they were already perking back up.

Then it rained, and rained, and rained some more yesterday afternoon. The stuff had plenty of time to dry, but I just don't know. My roses are not happy with all this moisture, or maybe they are but the fungus is doing the Marcarena and having BBQ's.

My grandma uses a Garden Safe product that has Neem Oil I think? I'm not really sure, but she swears by it and her roses aren't defoliated like a few of mine. But then again they are knockouts, so I can't really say if that's a good testimony for it or not as I don't grow those yet.

As for fertilizer, I just bought Mills Easy Feed liquid. I've added the link. Haven't used it yet and with all the rain, will probably wait till things dry up a bit. I have plenty of Rose Tone to keep them happy until then. It doesn't get cold in my neck of Florida until December so I have so extra wiggle room. I've also used Neptune's Harvest Fish/Seaweed emulsion. I used it on everything in my garden.

Here is a link that might be useful: Mills Easy Feed

Chaoticdreams,

Knockouts are one of the best BS resistant roses on the market in most areas but not all...
That may explain why your grandmas Knockout keeps
most of its leaves...

Yes, one of the best ways to grow roses organically is to select disease resistant varieties.

Yeah, I know about the knockouts being disease resistant, one of the main reasons they are super popular here. I'm even starting to come around to liking them. However, it's very humid here in NW Florida and its definitely stretched that resistance. She still has BS on them, just not as bad as some others around town and definitely nothing like my twigs. That's why I said I can't really know for sure if the Garden Safe works or if its just the resistance in the plants LOL.

:)

My twigs have until cooler weather to start behaving or they're gone. Plus, some of the problem was due to the grass in the yard getting out of hand and my entire house coming down with the plague and unable to weed or cut it. There was very little air circulation for my plants. Out of 40 roses, only 5 have been problem children so I am quite satisfied with the ones I picked. I'm more of a buy what you like person as I don't mind spending extra time on things I love. Spraying doesn't bother me as it gives me time to enjoy all the money I've shelled out this year.

Bayer Disease Control for Roses. . . etc. is probably the most effective product and will give you good control of blackspot if sprayed every two weeks. This is what I am using. Try Lowe's or online. The only "organic" fungicides that are likely to help much under severe conditions are copper products such as copper soap (Soap Shield). Copper should be handled with the same caution as synthetic fungicides. Also it can burn foliage. It is best sprayed at a time it will dry quickly, not at dusk or in the fog. I have used sulfur fungicide with some success, but only if I started at leaf-out and never missed a weekly spray--or more often during rainy spells.