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anntn6b

Sweltering heat may enhance spread of RRD.(long)

anntn6b
17 years ago

I think those on this group who know me know that I like to have lots of observations before I make statements about Rose Rosette Disease.

This time, IÂm breaking my own rule requiring that I have evidence from several sources before I make statements about observations of the spread of RRD.

But the very hot temperatures that many of us are seeing relatively early in summer have me very worried.

IÂve been worried because of reports of RRD coming from parts of the US where RRD hsnÂt been a major reported problem before.

But when I read Rhonda on the Antique Rose Forum described a situation,"Its so hot here, that late at night, you can still feel intense heat rising from the ground.." that has made me put this in writing.

I I have only my own garden experience as a guide, but this summerÂs heat means it might help some of the rest of us.

I grow between 500 and 600 roses in the ground. IÂve been dealing with RRD infections in my garden for six years. My approach is to quickly rogue out any infected roses as soon as I see the problem when the temps are over 60F- to try to prevent RRD spreading within my gardens.

Most years we loose two or three roses to RRD. Most infections seem to enter the garden in fall; sometimes we see the first symtoms in fall; sometimes we see the problem in spring, when the problem has spread to additional canes.

One or two roses out of 500 isnÂt a terrible loss; we loose more than that to voles.

BUT, one year we lost twelve roses to RRD that came into the garden in fall.

There is only one thing that made that fall different from other hot and dry falls: that was the fall that heat and drought combined to so bake the soil that it stayed hot after dark and radiated heat well into the morning hours.

What I think happened was that heat+drought afftected the upwind R. multiflora infected with RRD to the extent that the mite population was compelled by degradation of their microenvironment to leave. And at least twelve found my roses.

I lost 2%.

Since that year, RRD has increased upwind, but IÂve never again lost 2%, even though thereÂs more RRD ...hideous thought.

So...please take this as a gentle warning to start watching your roses for symptoms of RRD if your soil gets hot and stays hot. You may not see the RRD appear immediately, but...maybe vigilance can save some roses.

Ann

Comments (28)

  • sammy zone 7 Tulsa
    17 years ago

    Ann, you are such an expert, that I hesitate to post. I feel that the hot weather can create "false RRD". We water so much, and the heat is over 100. Suddenly many roses grow fast with odd shaped blooms. The leaves are too close together and they may have little bitty blooms (possibly caterpillars help this.) If you wait 2 ro 3 weeks, everything sort of evens out. I find this mainly on my red roses.

    Sammy

  • buford
    17 years ago

    Is there anything we can do besides be vigilant?

  • anntn6b
    Original Author
    17 years ago

    Yes, the heat can do funny things to rose development and you're right.
    But RRD may not show up until several weeks or months after the heat is over.
    And example. We had grubbed out a massive R. multiflora and thought we had taken it out before RRD got into it. The ground was cracked, nothing was growing and there were four rather puny stems left - and we had had NO rain, and one of those stems had breaks at every leaf axil and they went from nothing to five inches long in two days. Color of the new aberrant growth amber green; color of newer multiflora growth on fencelines (at least the last new growth that had happened) bland green.
    Never look at just one part of the plant; look at leaf margins, sepal edges, and see how fast the new growth comes on. (And when the plant has RRD, chances are the sexual parts of the rose will be messed up or even missing.)

  • buford
    17 years ago

    I wish I had taken pictures of my deformed roses that I'm sure had RRD. The flowers were so weird, puny and almost fringe like.

    I've seen growth similar to RRD on some roses, usually during spring and fall cold spells, but when it keeps coming back after you cut and cut, it's time for it to go.

  • patricianat
    17 years ago

    Ann, what you say is making plenty of sense to someone who has experienced a lot of RRD within a growing season ,as last year when we had our own "big dig" related to RRD, the weather had been very dry. We did not see all those roses at one time and I am convinced the RRD did not show up all at once. It was not only a hot dry summer, but a dry fall as well.

  • melva
    17 years ago

    I hesitate to ask this...but here goes..I have a Multiflora growing, that was rootstock from a departed Gallica...does the Muliflora need to go? It seems healthy and blooms a lot...I kind of like it..but...

  • anntn6b
    Original Author
    17 years ago

    Melva,
    Multiflora in and of itself isn't bad and the spring bloom and the way it scents the garden is truly grand.
    What I should have done with our big one was keep it under control from the getgo. But I let it get massive and the massive form makes a baffle to trap based on aerodynamics the RRD vector mites.
    I now am growing a multiflora (on purpose as opposed to along fencelines where they are harder to control) and I'm using it to experiment with different kinds of rooting on the mist table (and finding that it roots oh so easily). I want to be able to reproduce roses that get RRD before RRD goes through the whole plant. With this plant, we cut it back in early fall to almost nothing and it comes back and we enjoy the bloom, but we'll never let it get massive.
    So, you get a yes and no answer.

  • Molineux
    17 years ago

    My experience (although limited) has been that the larger the rose the greater the chance for RRD. Multiflora is the primary host plant because it is plentiful in the wild and forms HUGE thickets, thusly it is the most likely rose to encounter the mite that spreads the disease. NEW DAWN for example is a wichuraiana climber that is very prone to RRD (I had a neighbor who lost several). Why? Because it is a very common, very big climber. Large shrubs, standards, climbers and ramblers are usually the first hit by this horrid disease.

    Thanks for the warning Ann. I'll keep an eye out.

  • anntn6b
    Original Author
    17 years ago

    I really wanted to be wrong on this one.
    BUT, today I found RRD on our R.multiflora platyphylla 'Seven Sister' that is/was growing along the fence line.
    RRD on two canes, showed up in the past four days. Our temps have been hideously hot this summer with over 30 days over 90 already this summer and August and September are historically our hot temp months.
    Damn, damn, damn, damn.
    Ann

  • zeffyrose
    17 years ago

    Ann--I'm so sorry to hear this.

    You have such a lovely garden and I know how much you love all your roses.

    Thanks for the warning.

    Florence

  • olga_6b
    17 years ago

    Ann,I am really sorry to hear about your Seven Sister.
    Olga

  • kaye
    17 years ago

    Ann, could stress be a factor?? Lack of rain and the extreme temps..asking becuase of the breakout south of us.

  • anntn6b
    Original Author
    17 years ago

    Yes, Kaye,
    I think it could be stress to the RRD host plants that sends the mites airborne.
    What is so frustrating is that my garden has had decent rainfall this summer but the RRD areas along US 11W (about 3 miles upwind)have been much drier- parched grass, wilted weeds until about nine days ago- and I don't think it's that my target plants have been that much more susceptible for being greener, but that there are more mites wafting in.
    I would, however, like to thank Blush Noisette who engulfed me in a joyful mass of fragrance as I came back up the hill, dejected. I needed that gentle reminder.
    Noisettes rule!
    Ann

  • brother_cadfael
    17 years ago

    Hello Ann,

    I'm sorry to hear about your 'Seven Sister's', none of us likes to lose a rose, especially to something that we can't directly take the blame for.

    We just returned from vacation 1/2 an hour ago... we were in Cumberland Co., TN staying with my wife's parents in Crossville. My FIL commented a few times on how hot and humid it's been there for him this year even though he's on a plateau and hasn't had heat like this in the tens years he's lived there.

    They have several wild 'R. multiflora' growing around their 5 acre pond among blackberries, cattails, and ornamental grasses. They don't know the first thing about roses, and don't really care, but he did ask me what the strange growth on the wild roses meant. I immediately spotted the RRD, (unmistakable, even though it was the first time I saw it in person), I told him it meant he should dig up the bushes and burn them... but he's not too concerned about the whole issue, even after I gave him the unabridged version.

    On our 3rd day there we went to Burgess Falls State Park. There were dozens of wild roses growing along the trails, but I couldn't identify them as 'R. multiflora', they had different thorns and leaf edges, BUT I believe that 3 of the 40+ bushes we saw had RRD. I couldn't locate the ranger on duty otherwise I would have alerted him to it... who knows if they would even act on it anyway. My wife informed me that if I took 1 picture of a rose bush, I would be getting the "SPECIAL TOUR" of the high falls... so I don't have a picture to share.

    I'm really beginning to worry about RRD in Wisconsin, our weather has been so hot and humid this year, and with the majority of our rose stock coming from warmer states... it seems it's only a matter of time.

    Better Tomorrows,
    BC:)

  • Al Mitchell zone 5b (ameri2nal)
    17 years ago

    I've lost 3 big roses to rrd this summer. Darlow's Enigma, New Dawn, Gislane de Feligonde, and my 2 semiplenas have it, I 've been removing branches, but I think I'm gonna have to pull both of them. It seems like only my big roses are getting it. Weird.
    Al

  • wild_rose_of_texas
    17 years ago

    Ann and all,
    I just finally went over to Ann's e-book about RRD and read a portion of it this afternoon.

    It brings many questions to my mind, but the first one is the one that I am in a panic over: does anyone know if we have RRD in Texas yet, and if so, where is it? I do not recall having seen it here in northeastern Montgomery County. I hope I never will. But after reading the article, I can certainly sympathize with all of you who battle against this killer.

  • georgia_rose
    17 years ago

    Ann, so sorry to hear that your Seven Sisters has been infected. I'll be happy to start cuttings of the one you shared with us so you'll have a replacement if needed.

    Lisa

  • mark_roeder 4B NE Iowa
    17 years ago

    Your predictions on hot temps linked to RRD appear spot-on. I had never seen RRD, and Iowa State told me that they believed its presence in Iowa was limited to Southern Iowa. Iowa State acknowledged getting it at Reiman Gardens in Ames on a few of their plants. I noticed symptoms on mine just after the 100 degree days in July, although I did not know what it was, at the time.

    I removed a large percentage of my roses, today.

  • ogroser
    17 years ago

    Ann - Please post the url for your current RRD e-book. The one I have is out of date and I would like to take a look at it again to update myself. Thanks much!

  • melva
    17 years ago

    Allison,
    I lost a rose this spring, that had RRD and I am in Denton County..it was Excellenz von Schubert.

  • anntn6b
    Original Author
    17 years ago

    Right now the E-book is down for an update. And we're trying to do some more on a related site.
    I will be crowing in delight when we get things back up.
    Ann

  • Embothrium
    17 years ago

    Plant-sucking mites often said to like hot and dry conditions.

  • anntn6b
    Original Author
    16 years ago

    Because of the summer drought, I think this thread may be even more suitable to the summer of '07.
    This year, we've seen RRD on the western end of Long Island (in the city). And there are more reports from Wisconsin.
    The ebook has a new address

    Here is a link that might be useful: Rose Rosette E-book

  • michaelg
    16 years ago

    Ann, did you check your stem-girdler topic?

  • carla17
    16 years ago

    Thank you for keeping us updated on these issues and others.

    Carla

  • anntn6b
    Original Author
    16 years ago

    The summer of 07 may be an additional test.

  • patricianat
    16 years ago

    Well, we started having a drought the year I lost so many, 2005, and last year still a drought but not quite as bad but with only 1 case of RRD that we noticed. This year it seems loss of roses to RRD will surpass 2005, but we cannot water to ensure it does not. We are under serious water restrictions.

    Yes, we hate losing our roses, but this drought is really bad. I am not sure how long we have before our household water is going to be monitored.

  • bbinpa
    16 years ago

    Ann, two weeks ago we ended a very hot spell. We are still behind in rainfall according to the weather man by 10 inches. Last Tuesday I found RRD on Arethusa-three canes. Cut them back to the ground and will keep an eye on it. I think these are the conditions similar to what you described. Night temps were very hot as well.

    Molineux, Arethusa is very small in my garden and surrounded by big roses. It is only about 2 feet tall and at least as wide. Its companions are easily 4 to 6 feet. I don't think bigger roses have a greater propensity towards RRD other than they are big enough to get in the way of the mite. I have found roses of all sizes get RRD in my garden. Last year I lost a mini, Lavendar Pink Parfeit to RRD.
    Barbara