As long as it's not any hotter and it stays dry for a while you should be able to spray. However, you may be fighting a losing battle. If the weather is going to stay damp the spores will just keep returning. 70s and damp is just about perfect black spot weather.

Alameda,

Bayer Advanced Rose, Flower, and Shrub Disease Control, once it's dried on the foliage, gives, "rain proof protection, lasts for up to two weeks". This is what Bayer claims. I use it and have excellent results. I would spray now.

Under normal sunny conditions it should be dry in about an hour.

Moses

I have this product.......we are due to have sunshine for quite a few days. Though it may get as low as 34 tonight, tomorrow's high will be mid 60's and will be this way for awhile, and sunny. Should I spray weekly? How long should I continue? Is the Bayer product a preventive or a cure? What about Mancozeb? Should I use just the Bayer or switch? I have never sprayed in winter so not sure what to do, but really want to do something about this blackspot and not go into spring with this problem. Thanks for the advice!

Judith

The warmer it is, the better the fungicide works. There is a point at below the low 50's for daytime highs when it is just wasting time and money spraying.

Moses

Thank you Moses! You are a wealth of information and I appreciate your comments, Seil's too! I appreciate the advice - I was cautious about spraying this time of year without good advice from knowledgeable growers. Thank you!

Judith

Hey alameda don't you take off all leaves anyway on Valentines Day when you cut roses back? I grew roses in H for 20 yrs and followed the guidelines of the Houston Rose Society. They are about showing roses, which I am not, but their Rosette Newsletter was full of good advice which I still follow here in Dallas. Cut, deleaf, clean beds, spray with Mancozeb, follow with systemic, work various organics into soil, wait for beauty.... this was their Feb routine. It always killed me to cut off all the new growth, buds & flowers that Houston weather sometimes produced by Feb. but when I did not I paid the price later. One more suggestion Rosemania has a great spray routine with much better products than Bayer (longer lasting) I follow their product suggestions but often order from Amazon because less $$. You probably know every bit of this information and HRS may not be what is was when I lived in H. The advice section of Rosmania is helpful if you have not discovered them. H was not an easy location in which to grow roses. I never knew that until I moved to Dallas. Good luck!

Thanks Austin! I am a member of the Houston Rose Society - to get their newsletter. I dont deleaf my roses - I have too many, so have normally waited til spring to prune and get rid of unsightly leaves when I prune, but this summer and fall, I had so much going on with the passing of my mother, getting 2 properties ready to sell, my Navy son leaving for deployment - I was doing good to get them watered! Now that I have a little more free time - I am just hating the blackspot and want to do a little something to try to combat it but have never sprayed this time of year. And I am careful to prune right at Valentines Day - I have delayed with this before and, like you, paid the price. Our weather, being 2 hours from Houston, can warm up quickly in February and roses take off. If I wait too long to prune - they are all leafed out and making buds, and if pruned too late, are set back. I know of Rosemania - thanks for the tip - I am going to look at their website. Since we are due some nice, warmer weather.......want to take advantage of it and get maybe one spraying in to help combat blackspot. Hopefully in spring I can get back to a more regular routine. But I didnt want to spray then see the leaves have a bad reaction to it.

Judith

Ha you have more knowledge than I on this, did not mean to sing to the choir.

I really fought blackspot when I lived in H. I lived close to Galleria by loop and it stayed warm even if elsewhere got freeze. Never got rid of bad bugs to add to the bkspot issue. Loved growing those fabulous tropicals in with my roses esp. alamander henderson and thunbergia. You can grow the big deft blue ones that I loved. Here it is only the small flowered purple ones which are just not the same, and those ground orchids- fabulous... I could go on and on so many lovelies.

For me alternating Heritage and Honor Guard every 14-18 days really helped especially if I started fairly clean after Mancozeb. I used Indicate 5 because of hard water and that helped also. There I go "singing" again, guess I can't help myself.... I only had about 50-60 plants so I took those leaves off every last one. Hated that blackspot and back then not many roses were resistant. What type of sprayer do you use? Mine is battery Spot Shot but it is getting old and the company stopped making them. Could not find a comparable replacement when I looked online.

BR

You can grow gorgeous tropical hibiscus in Houston too......mine go in the greenhouse in winter but do fine. The humidity is a killer, almost unbearable in summer, bad where I live too - I sweat to death in summer. We do get winter which I love except for "pipe busting" weather, under 25 degrees. I have horses, so constantly have to worry about busted pipes. I grow alot of bands - enjoy seeing them become big roses - so have lots in pots that I baby [I dont count anymore!] I really got off schedule with everything this year and find myself with this blackspot situation, winter coming, and have not dealt with this problem before. I prune my roses back pretty hard in February because they come out and grow so much in spring, so would normally get rid of most of blackspotted leaves, put refuse in burn pile, spray plants and the ground and move on. But, it is really bothering me to see these diseased leaves. I dont have a fancy sprayer - dont laugh, but I mix up solution in a couple of gallon jugs and pour into a hand sprayer. Put the jugs on my golf cart and go around to the different beds and spray each rose really well. I am in process of organizing my pot ghetto - got my carpenter to do this stairstep shelf in my pot ghetto made of stair "stringers" and long wide boards he gave to me and put outdoor carpet I cut in strips for the pots to sit on. This will be really helpful to care for the smaller pots, easy to water and spray. I bought one of those smaller pump up mist sprayers, havent used one in a long time but going to try it out today. I have beds in quite a few different places, so dragging a bigger sprayer around doesnt work for me. Maybe one day I will find a bigger sprayer that would work........not sure pumping that mist sprayer all the time will be much fun - rather just do the hand sprayer I think.

Going to go spray this afternoon - weather is beautiful!

Judith

I am now and have been too old to pump or drag around hose end, and they always seemed to clog up .... also need to reach tall climbers. Battery sprayer is easy, never clogs, on wheels so moves easily around yard, has a 20++' reach, and holds 7 gal. which does my whole yard most months... Highly recommend if you get tired of pumping. Only downside is cost. Mine was very pricy. Wish I could find a replacement. Every Feb I keep my fingers crossed that the sprayer will work, no one around here will work on them. I miss Southwest Chem and Fertilizer in Belaire they fixed everything garden related. I got my first battery sprayer from them it only held 4 gal but was less than half the cost of the Spot Shot. I don't think they make there's anymore either.

BR

Are these electric or battery operated? Southwest Fertilizer in Bellaire is still open - I go every year in February when they offer Houston Rose Society Members 15% off. I have never looked for sprayers there......wonder if they have them? It aggravates me to have to work on a piece of equipment [that I probably cant fix] when I could be fooling with the roses. Guess that is why I just do the hand sprayer thing - its easy, if it quits working, I buy another one and move on. The Spot Shot sounds ideal! Surely there are sprayers around that work! I have a 15 gallon one that works by battery that fits on my golf cart that we use to spray fence lines. I dont mess with it but the man who works for me has never mentioned a problem......but that is way more than I need for roses.

Moses great info love to learn the why of things. For me Bayer never worked well in Houston or Dallas which is why I switched to alternating Honor Guard & Heritage. What is your opinion on them, all I know is that they work.

Alameda the sprayer I bought from Southwest was battery as is Spot Shot. It was around $200. It worked great but no one in Dallas would work on it once it aged out. When I was in H, I took it to Southwest every 3 years for a clean, tune up and new 9 v if needed. They charged very little for that service, great people. Love their HRS discount on product. Their organic mixture as good as Mills Magic and cheaper.
Spot Shot was $450-500. Big cost difference... it always works, no clogs no problems just battery replace. But hey, for that much $$ it should be trouble free. It is old now so I am looking for a replacement it it dies. Let me know if you find that SW still makes its battery sprayer. It was on wheels also and moved easy around yard. I think it had a 4-5 gal. tank.