If you're concerned about it the only other thing you can do is spray. I recommend Bayer Disease Control for Roses. Follow the directions carefully. It won't cure any leaves already infected but it will stop more leaves from being infected. You may notice more leaves spotting and yellowing after spraying. That's normal They are leaves that were already infected before spraying but just weren't showing symptoms yet. They will continue to spot, yellow and fall off until all the previously infected leaves are gone.

And remember that "very disease resistant" does NOT mean "disease immune." Any rose can get BS if the temperatures and other weather conditions are conducive, but a "very disease resistant" rose would hopefully do a better job of resisting--but not necessarily eliminating--BS.

Are your roses getting at least 6 hours of sun per day? Are you leaving air space around the rose as well as within the rose? Are the roses well-watered and healthy? Any of those factors, if not carefully maintained, could make it easier for the rose to succumb to a BS attack, though hopefully not as much as a disease-susceptible rose would.

If you only have a couple roses, the Bayer could be too much. You could try a ready-mix bottle of Daconil available at Wal-Mart.

Kate

Answers to Kate's questions:

Yes, the roses are getting at least 6 hours a day of sun. They were flowering profusely and still have blooms.

There is plenty of air space around and within the rose bushes.

They get watered frequently along with the rest of the garden. Water should not be a problem.

The roses were basically healthy except for holes in the leaves made by sawflies. As I said, they have been blooming profusely.

So--do I need the Bayer or what?

If you want to eliminate all blackspot, you will have to use a fungicide. Bayer Garden Disease Control (but NOT one of their combo types--read the labels carefully) is excellent, but is usually made up in a 2 gal. container. Do you need that much? If not, Daconil comes in a smaller ready-mix spray bottle. It is good, but not as good as the Bayer product.

The reason you are not getting a strongly affirmative response is that spraying is a highly controversial topic. It may not be good for your health or for the environment--it may kill off some "good" bugs that you want in your garden. On the other hand, it is approved for use in the home garden (in which case, follow directions carefully). So you have to make up your own mind which way you want to go.

Sometimes a rose gets a limited case of BS, so rather than spraying, many gardeners just tolerate the less than perfect leaves and pick them off (dispose in garbage, not in the compost pile) as they turn yellow. You don't want to pick off green leaves, if possible, because the plant gets its energy from the sun through the green leaves.

I try to limit my spraying to a couple times in the spring and a couple times in the fall--the two periods of time most conducive to the formation of BS. Some gardeners spray every 2 weeks all season. Other gardeners refuse to spray under any conditions.

In your case, I'd try first plucking off the yellow BS leaves and see if that is enough to get the problem under control. But if it kept on spreading and getting worse, then I'd use Bayer Garden Disease Control twice (about a week or 10 days a part).

Kate

Its August. Roses tend to look their worst in August. In most areas of the US, its too hot to spray now without burning the foliage. If less than a third of the bush is defoliated, I would not spray. If more than a third of each bush is defoliated, I'd purchase a small, hand held bottle of Immunox or Daconil at Home Depot as Kate suggested: water heavily the day before and spray early in the morning at first light. I understand that you want your roses to be as healthy as possible, and its your choice whether or not you spray. Personally I think you're overreacting to a dozen spotty leaves.

The active ingredient in Bayer (tebuconazole) isn't approved for home use in New York. If you really feel the need to do something, a bottle of Immunox isn't out of the question.

I think, having removed as many yellow leaves as possible and tossing them into the garbage can, and having pruned away weak canes to make more air circulation possible on the Strike It Rich rose, that I will adopt the "wait and see" position. Thus far, the vast majority of the rose bushes is still green.

The yellow leaves are primarily at the bottom of the bushes. The Easy Does It rose bush has much bushier growth because I did corrective pruning on it for the 3 years I've had it. I will have to do the same to the Strike It Rich rose bush, as I only got it this spring. It consists of a base of old brown cane from which spring many green canes, most of them weak. I had to prop up a lot of the canes while they bore flowers. Now that the weak canes finished flowering and have no more buds, I trimmed them off to allow more air circulation. I trimmed off any crossing canes. Right now, there is ONE big long cane growing off the base of old brown canes which is flowering nicely. The other green canes growing off the old brown cane base are done with flowering, and I deadheaded them. If they were really spindly, the whole cane came off, into the garbage can.

I really hope that next spring, the Strike It Rich rose bush will have a lot better, stronger canes than it did initially. Despite that, I have been utterly delighted with the beauty of the flowers, as have many of my neighbors. It bloomed a LOT, and the amber-yellow flowers streaked with red are breathtakingly gorgeous.

It is also possible that some (all?) of those yellow leaves are just old leaves that the bush is getting set to shed in order to make room for new leaves. Rose bushes are known to do that from time to time.

And I agree with you--don't rush into spraying for BS until you determine how much of a problem your rose will or will not have with it. We'll hope this was a one time outbreak only.

Kate