How often do you spray Hybrid Teas?

zack_lauAugust 10, 2013

I missed a spraying and sure enough, some of my HTs are showing signs of blackspot--going 4 weeks without spraying is too long, even for Bayer Advanced disease control.

In the past, I've found that spraying Immunox every week works well, as does Bayer Advanced every other week. We have a humid climate--50 or 60% is hardly unusual, it is 80 degrees and 60% humidity right now. Rain in the past month has been 5 inches--on six occasions we got at least half an inch of rain.

Wonder what works for others if you want fully foliated Hybrid Teas throughout the growing season?

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Here in my Louisville,Ky garden I spray every 7-10 days. My H.T. roses retain most of their leaves...I pick a few off here and there. I become a little lazy come Oct. and end up with more de-foliated bushes. You would think I would learn. I guess I just run out of steam! Lesley

    Bookmark   August 10, 2013 at 5:06PM
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ingrid_vc so. CA zone 9

Another alternative would be to find roses that do well in your climate without spraying, although that might not include many hybrid teas, and would probably limit you in varieties of roses overall. I'm too wary of the long-term effects of toxins to spray at all, especially on children, pets and wildlife, but that's easy for me to say since I live in a dry climate. Even so, no matter where I lived I wouldn't spray, especially with the frequency you talk about. It's just something to think about, and a decision everyone has to make for him- or herself.


    Bookmark   August 10, 2013 at 5:30PM
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I spray every two weeks. Chicago.

    Bookmark   August 11, 2013 at 1:23AM
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I considered other options--my wife would love to see bougainvillea and camellias, but neither of those will grow in our front yard without greenhouse support. We do have a pretty good sampling of old garden roses--a couple dozen popular varieties, but she prefers Hybrid Teas.

This post was edited by zack_lau on Sun, Aug 11, 13 at 9:56

    Bookmark   August 11, 2013 at 9:54AM
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michaelg(7a NC Mts)

I tried expanding from 14 to 21 days with Bayer, and with a rainy mild summer, I got quite a bit of disease. Cercospora was worse than blackspot. One rose defoliated--not a HT but 'Gruss an Aachen'. In very hot or dry weather you could get away with that or longer intervals.

Every two weeks works great with Bayer (and with propiconazole products, they say). Triforine (the Ortho rose fungicide) applied every 7 days did not control as well as
Bayer every 14 days.

This post was edited by michaelg on Mon, Aug 12, 13 at 11:43

    Bookmark   August 11, 2013 at 12:14PM
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nickl(Z7a NJ)

We follow the label direction for those roses that we have on a fungicide program.

If the label says 7-14 or 7-10 days (many products), we schedule for seven days. If it rains on that day, or if conditions are otherwise unsuitable for spraying, of if we are unavailable to do the work, we still have a leeway..

Similarly, if the label says 14-21 days (e.g., propiconazole), we schedule for 14 or 15 days.

Following that routine, we have kept BS and PM under control.

    Bookmark   August 11, 2013 at 7:04PM
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Ingrid Bergman is one of the more disease resistant roses in our garden. The big red cane on the left belongs to Cajun Moon. It gets morning sun--east facing garage wall. it is four feet tall. Due our shorter growing season, we only need to spray six months out of the year--it is too cold for BS during the rest of the year.

This post was edited by zack_lau on Sun, Aug 11, 13 at 20:07

    Bookmark   August 11, 2013 at 8:00PM
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I'm fortunate to almost never get BS. I get occasional mildew, also whiteflies an aphids. I spray when I see a problem.

    Bookmark   August 11, 2013 at 8:32PM
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I leave in NJ, and thanks to helpful hints from this forum I started spraying my roses with the BA disease control. This has worked like magic for me! I started this year for the first time and here are the dates on which I sprayed my HTs:
June 9
June 21
July 7
August 1
Might spray again this week but don't really see any BS yet. Note that my HTs were almost gone due to BS, now they are thriving. Just follow the directions on the bottle and spray. I also saved my left over solution from the 2 gal sprayer and re-used it. No problem,

Hope this helps,

    Bookmark   August 19, 2013 at 8:10AM
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nickl(Z7a NJ)

Hi Enjay

I'd say you were pushing it. First, you started too late in the season for blackspot. Second, Bayer is labeled for a 7-14 interval and you are considerably exceeding that. Maybe if conditions are very favorable, you won't get an outbreak. But I can guarantee that in many years you will get disease on your susceptible roses if you follow that schedule.

As for keeping excess spray solutions around - it is NOT recommended. The chemical reactions start immediately when you mix the concentrate or powder with water, and there isn't anything you can do to stop them.

Here is a link that might be useful: Applying Pesticides Safely

    Bookmark   August 19, 2013 at 10:31AM
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dublinbay z6 (KS)

I'd say that if Enjay's schedule works for his roses, then more power to him! If in the future that schedule is no longer adequate, he can always change it to fit the changed circumstances.

I agree, however--don't keep extra mix standing around. If it takes less than 2 gals to spray your roses, then make up only a gal. of it.

When I estimate wrong and end up with some extra spray, I give other things growing in my garden a quick once-over. After all, garden phlox has trouble with mildew and doesn't object to an encouraging quickie spray.


    Bookmark   August 19, 2013 at 2:36PM
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I work in chemical research industry, especially organic chemistry, so I tend to research chemicals before using them. The active ingredient of the product we are discussing is tebuconazole. This is also sold as 'Ready to Use' spray which is mainly water + tebuconazole. Moreover for those interested you can search for stability of this azole in water, it is stable. Manufacturers prefer us to discard the unused portion simply because it means more consumption. If you store this water solution for two to four weeks this will stay stable, there will not be any reaction with water (hydrolysis). This is also a slightly 'greener' approach as you are not throwing away the unused portion. Oveall I agree though that one should mix only what is needed and not more. I will post more info if I find something new, or my solution goes bad on me.
Nicki, I started late because I learned about this product late. I am anxiously waiting for the next season where I can start from day one!

    Bookmark   August 20, 2013 at 7:36AM
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michaelg(7a NC Mts)

Some chemicals, like mancozeb, are unstable. Enjay is correct that tebuconazole is stable in water over a wide pH range. If the sprayer is secure from children, etc, it's acceptable to save the leftover. Possibly doing so could lead to clogging, though, or you could forget what is in the tank. I mix what I intend to use and spray any small leftover amount on daylilies and other fungusy ornamental plants.

    Bookmark   August 20, 2013 at 10:42AM
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Maryl zone 7a

Well, this is a good conversation. I didn't know about the Bayer fungicide being stable. In our hot area, that may mean I could mix it up the night before and spray early the next day. I'm not a morning person, so fiddling around with chemicals is not a good thing for me in the AM.....Also, excellent point about clogging the sprayer. If you leave the product in a used but unwashed sprayer you could very well have problems later on.....As for products to use and when, I've been more then happy with Fungunex for B.S./P.M., and only because of the spraying intervals do I alternate with any other products now such as Banner Maxx or Bayer. I can go 2-3 weeks with either of those two whereas with Fungunex it's 10 days max before required spraying. But, Ortho's Fungunex is excellent at powdery mildew control, so I tend to use it more when those diseases are prevelant in spring/fall....Also as to when to spray, one needs to spray when conditions are ripe. During our last two summers from Heck, with temperatures exceeding 105 and more, I stopped spraying in May and didn't restart until late September. Not a problem. This year I tried doing that and with the intermittent coolish spells and rain we've had, I've got some roses with B.S. as well as cercospora leaf spot. I've started spraying again......Maryl

    Bookmark   August 20, 2013 at 3:49PM
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Zack -- BS is a serious problem for about half of the roses in my coastal Carolina garden. I succeed in keeping the disease at bay by spraying Honor Guard once every three weeks. Every spring I mark my spray days on the calendar for the entire season and keep rigorously to that 21-day schedule -- adjusting it only if rain is predicted.

Honor Guard has the the same formulation and active ingredient (propiconazole) as Banner Maxx, but is less expensive. A very little amount goes a long way (1/3 teaspoon of Honor Guard to a gallon of water). Gardeners in other zones tell me that it's also very effective in controlling PM, anthracnose & rust -- altho rust control apparently requires a slightly stronger solution.

ND1964 -- Re your comment, **might spray again this week but don't really see any BS yet**. IMO, if you're going to resort to spraying your roses, it's very important to establish a rigid schedule. Often leaves are hopelessly infected BEFORE you see the evidence. Most spray products are preventatives, not cures, and spraying those products will not stop already-infected foliage from exhibiting the tell-tale spots you're hoping to avoid.

Michaelg -- FWIW: I know we've all been told time and time again that 'Gruss an Aachen' is a Floribunda -- in fact, that its arrival on the scene heralded the advent of the Floribunda class. Not so, say Gregg Lowery (Vintage Gardens), Brent C Dickerson, and several European authorities. They insist that GaA is rightly classified as a Hybrid Tea. So, according to them, that rose of yours that totally defoliated is an HT afterall . . . ;-)

    Bookmark   August 20, 2013 at 3:56PM
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Windeaux, point well taken. sprayed this afternoon already - takes me 10 mins or less for my six roses.

Others, in general I feel that any spray that is available as a concentrate or a 'Ready to Use' ought to be stable in water. Of course as Michael pointed out storing these does not take into account factors such as safety, clogging etc. I have a sprayer that is dedicated to BA disease control which mitigates the risk of getting my sprays mixed up.


    Bookmark   August 20, 2013 at 4:06PM
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Not surprisingly, location makes a big difference--the HTs in the front yard look really good--they have a southern exposure and very good air flow.

But, in our main rose bed, the HTs on the eastern side are fully foliated (morning sun), while many of those in the western side with some shading from a big maple tree have had severe BS and defoliation. They all grow to 4 feet or taller and bloom vigorously when sprayed, so by most standards, they do get sufficient sunlight.

Fortunately, I may be able to locate all the suffering HTs to better locations next year!

    Bookmark   August 22, 2013 at 10:24AM
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idixierose(z8b Coastal SC)

I follow a 14-day schedule, rotating Honor Guard, Compass and Heritage, plus Pentathlon.

I often supplement this with a Pentathlon spray either before or after a rain.

    Bookmark   August 24, 2013 at 1:36PM
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dan_keil_cr Keil(Illinois z5)

I read this whole thread. I never saw anything about what the label on the product says. that should dictate how often you spray. If you are not following what is on the label, then you will get disease on your leaves. The label also tells you about storing leftover spray.IF YOU WANT TO KNOW, READ THE LABEL!

    Bookmark   August 26, 2013 at 12:45AM
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They all grow to 4 feet or taller and bloom vigorously when sprayed, so by most standards, they do get sufficient sunlight.

    Bookmark   August 26, 2013 at 8:59AM
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Experienced gardeners certainly familiarize ourselves with label instructions and take those recommedations into consideration. We don't, however, slavishly allow those generic instructions to DICTATE how we incorporate products into our care regimens. Requirements vary wildly among rose varieties; they certainly vary from one locality to another; they fluctuate seasonally within localities; and, depending on weather patterns, entire growing season often vary radically from one year to the next. Disease pressures fluctuate accordingly.

Observant gardeners attempt to balance the variables, and strive to develop and maintain care programs that are safe and effective for their unique set of circumstances.

    Bookmark   August 26, 2013 at 9:32AM
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duplicate post

This post was edited by jaxondel on Mon, Aug 26, 13 at 10:07

    Bookmark   August 26, 2013 at 9:41AM
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