I'm not sure the 85 degree rule applies to all fungicides, but I spray in the morning before 10:00. That gives the leaves time to dry before the hot mid-day sun hits them. If I weren't lazy, I'd actually spray about 7:00 in the morning--when it is cooler for me!

If the 85 degree rule applies, I'm sure it is limited to #1.

May I suggest you do NOT spray the 3 in 1. It includes an insecticide that usually is not needed at all. All it does is kill the "good" bugs that would have preyed on the "bad" bugs if they showed up. If blackspot, for instance, is your main problem, just get the fungicide only. For Bayer products, that would be Bayer Advanced Garden Disease Control for Roses, Flowers, and Shrubs--available at Lowes.

Kate

I have a related question that maybe someone can answer. How long should the fungicide spray remain on the leaves before rain or water sprinkling to be effective? Sometimes it's hard to find a day without rain to do my spraying and knowing this would be very helpful.

Thanks!

The answer to both questions depends on what is being sprayed. Bayer Disease Control doesn't burn under normal conditions and needs an hour or two to be absorbed into the leaf before rain..

So i see a lot of people are using Bayer for a fungicide, i take it that it is a good product to use for Black Spot? I used some Bayer weed killer in my yard and i wasnt terribly impressed with it so i didnt think much about the rose spray. Would you recommend it? Is it the systemic one that last for 6 weeks or do i need to spray every 1-2 weeks? Thanks

I have Spectricide with Immunox and another spray i cannot think of the name right now.

The Bayer fungicide (and you want the fungicide only) works very well if sprayed every two weeks, and fairly well being sprayed every three weeks. I've sprayed in the middle of very warm days and never had any problems (other than a touch of heat stroke, but that's what I get for spraying on hot days).

I've been told that once the fungicide has dried on the leaves, that it is rain proof. I don't know for sure if that is a true statement, but when I used to spray, it seemed to work out O.K. This is for a systemic fungicide, and not one that coats the leaves only. Some fungicides wash off.

The best time to spray in the summer is early morning after the dew has dried, or in the evening before sunset, preferably in time for the product to dry before dark.

Sandy

The 3 in 1 isn't a spray, it's a drench, and it also includes an insecticide and a chemical fertilizer. The fungicide only is Bayer Advanced Disease Control. Home Depot does not carry it, you have to go to Lowes. It's a milky white concentrate. I use it every 2 weeks, 3 weeks in really hot weather. I usually spray in the early morning before the sun is high. I've sprayed on warm mornings when it's probably 80 degrees or close to it, and never had a problem.

It's a systematic so it does need some time to absorb into the leafs before rain.

Today I used a systemic drench for black spot on my roses.
Should I also spray them weekly or will the drench be enough
every six weeks. My Simplicity hedge roses & I will appreciate your thoughts. Thanks DL

I'm guessing you are in Florida where Simplicity is highly susceptible, but if you are in California no fungicide may be needed. Nobody here recommends the drench products as they involve applying unnecessary chemicals in much larger amounts than if sprayed. Go ahead and use it up, but shift to a spray containing tebuconazole or propiconazole.

If you are just using roses as landscape plants in Florida, Simplicity is a poor choice. You can avoid spraying by replacing with any of the Knock Out roses or the wonderful old China rose 'Louis Philippe.'

Thanks michaelg for your comments. I live in Roseville,CA zone 9 and I planted my roses last year. This my first attempt
at raising roses and I love this hedge,however last year I didn"t use a dormant spray and I believe this black spot was
already there, The top of my bushes look very healthy but a
lot of leaves on the bottom are infected. Will these grow back? What dormant spray should I use ? Thanks so much for
taking the time to answer my questions, DL

Diane,

Maybe you need to hear from someone in your area, but from what I understand, you needn't be much concerned with blackspot in the Central Valley. You might get a little during the winter or early spring, but soon it will be too hot and dry for any fungus disease to spread. Blackspot spores need to be wet for 8-12 hours at moderate temperatures in order to germinate. Be sure not to wet the foliage in the evening when it might stay wet all night.

If you can post a sharply focussed close-up of a sick leaf, we could check on your diagnosis.

You could pick off and bag the infected leaves if you want to. It will help a little bit and they are going to die anyway. Lower leaves will not grow back, however.

I don't use a dormant spray myself, as it does minimal good at best. Here we need to spray fungicide all season on almost all rose varieties.

Good luck with your hedge. I'm sure it's beautiful.