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jpbellis

Blackspot has defoliated my roses .. now what

jpbellis
14 years ago

Well, This terrible wet and cool summer in the northeast has certainly taken its toll on my roses. I've been in an all out battle with blackspot. I've managed to keep some of them reasonably healthy but one has lost nearly all its leaves. This plant is now pushing new growth from the spindly tips of the leafless stems, about 3 feet up. What is my best course of action? Prune it low like it were spring? Thoughts?

Comments (19)

  • michaelg
    14 years ago

    What are the tactics on your side of the "all out battle"? Blackspot can be fully controlled with modern fungicides.

  • User
    14 years ago

    What Michael said. It all depends what you mean by "all out battle". I suspect your artillery did not include an appropriate fungicide.

  • jpbellis
    Original Author
    14 years ago

    I suspect you don't live near CT or new England... We're nearly 20" of rain over our normal, with never more than 2 days of sun in a row before we get more water. And its been very cool. I've been gardenening for many years and never experienced months of bad weather like we've had. Topical treatments don't stand a chance if they aren't allowed to remain on a plant. Gardens everywhere are just rotting with many folks not getting any veggies etc. I use Ortho and Bayer Advance products and have had wonderful success over the years. Many of our roses have been okay but a few just couldn't be kept free of black spot.

  • ocngypz
    14 years ago

    This is the first time I've had serious BS problems. The only two not affected are Lavender Lassie and Crepuscule.

    I've cut the buds off the affected plants so they'll put their energies into foliage...and well..........I'm just praying for sun, sun, sun. All plants have full day southern and eastern exposures.

    It's been a miserable summer. Thank goodness the spring flush was spectacular!

  • mad_gallica (z5 Eastern NY)
    14 years ago

    Yes, and....

    Actually, the blackspot hasn't been bad at all here. Much less than I would consider 'normal'. Of course, I've also spent the last decade weeding out roses that don't actively like this climate. So the ones that would prefer more heat and less rain left a while ago.

    May I strongly recommend a shovel. It will save you some heartache the next thing times don't go exactly as 'normal'.

    BTW, big piece in the local paper this morning on how they are expecting a very excellent apple crop this year. Maybe you should plan on coming and getting some.

  • User
    14 years ago

    "Topical treatments don't stand a chance if they aren't allowed to remain on a plant."

    Not true. Any formulation with Propiconazole remains active (absorbed into the leaf) as long as it has time to dry on the plant after spraying. Even under the worst conditions, it will protect the plant for at least 7 - 10 days before reapplication is needed.

    And as mad has suggested, deal with the worst offenders by digging them out and replacing them with roses that perform better in your climate.

  • jpbellis
    Original Author
    14 years ago

    trospero ... your key operative in your response is ...as long as it has time to dry on the plant after spraying.
    Thats what I've been saying ... It has rained for 4,5,6 days straight many many times this year.

  • ramblinrosez7b
    14 years ago

    I would take all the infected leaves off and just wait, it will grow more leaves. In the meanwhile spray the canes with a fungicide. As soon as the new leaves start opening I would start spraying, canes and all. I spray when leaves are wet, especially in the morning when dew is on the leaves, have to or else I could never spray, just too busy in the evening.

  • jerijen
    14 years ago

    Well, but I agree with the suggestion -- if only two of your roses are so troubled, perhaps the time has come to part with them.
    Grow something that is less susceptible to disease.

    Jeri

  • User
    14 years ago

    OK, but you also said "We're nearly 20" of rain over our normal, with never more than 2 days of sun in a row", which suggests that you still have plenty of opportunity in any two week stretch to get the job done :-) I don't mean to sound argumentative, I'm just going by what you have said about available dry periods.

  • michaelg
    14 years ago

    Systemic sprays like Bayer Disease Control don't have to dry completely (although that is best)-- they just need a couple of hours to soak into the leaf. If foliage is wet when you spray, spray a bit extra to displace the dew or rainwater.

    If you have leaves, you can save them by applying Bayer tebuconazole immediately. I wouldn't prune severely, as there is some energy stored in the canes. Your plants are in danger of having their carbohydrate reserves depleted so they can't come back from winter.

  • jaxondel
    14 years ago

    jbbellis -- I spent 3 weeks in central VT earlier this summer and totally understand the predicament gardeners in your region have faced this season. We arrived for our holiday in a downpour, departed in a downpour and spent most days marooned indoors because of a downpour in progress. Some of the comments here seem to suggest that you're whining about a situation that you could/should have prevented. It's a view that I don't share.

    Some days when it wasn't raining, foliage remained wet. Moreover, those precious few 'dry' days during our stay did not once coincide with a weekend -- which, of course, is when major gardening chores (like spraying) are done by those of us who are employed & don't have the luxury of paid groundskeepers.

    If anything MIGHT have worked to salvage your roses under such extreme conditions, it would probably have been a systemic like Bayer's All-In-One soil drench applied early in the season and then once again a month or so later if necessary. All-In-One is not a product that I would never endorse with enthusiasm, but I don't know what course I might take if I knew in advance that I was to face a totally water-logged season like you've endured this year.

    Gardening is always a roll of the dice. Here's hoping the roses in your garden will be spectacular in 2010 -- and that the rain goddess won't be in such a tizzy!

  • buford
    14 years ago

    jp I feel your pain. Like you we had a lot of rain in the spring and I did not get to spray when I should have and many of my roses suffered.

    I did cut back a few of the worst ones to about 18 inches and they did rebound and leaf out fully. It's worth a try if they look absolutely horrible and you can't live with it. It will take a few weeks for them to recover and you'll need to fertilize and water (if it's stopped raining!).

  • roseman
    14 years ago

    Just keep spraying - new foliage will come.

  • chardie
    14 years ago

    I feel your pain. I thought three of my roses had croaked last year because they lost all their leaves to blackspot. I live in CT also, but this year my roses are great--they're loving the rain! I'm able to spray with Ortho or Bayer. I haven't used a fungicide, just the combo products for insects, etc. I think as long as they stay on the plant for 45 minutes or so, you're covered, so that's what I've been doing, amidst all this horrendous rain! Hang in there, maybe it's just an off-year for you.

  • zack_lau z6 CT ARS Consulting Rosarian
    14 years ago

    I sprayed my roses yesterday. Sure, we had a light sprinkle in the middle, but I doubt it washed off all the fungicide. It was about 2 hours until it really rained--so I'm not going to spray again for roughly 2 weeks. I've also sprayed in the early morning, while the leaves were still wet. We have a little BS--but no plant has more than a few leaves with it. It was even dry enough to fix my older 8 year old 1 gallon sprayer after I finished spraying--the O-rings in the shutoff valve dried out--for a temporary fix I just greased them--I'll eventually buy the refurb kit and replace them.

  • SoFL Rose z10
    10 years ago

    Everyone says new foliage will come, but do you want foliage starting at the top of the 3ft canes? I've rarely seen roses leaf out from the bottom once they loose leaves to BS. I think trimming them down is really your best option. If a weak rose has to spend a lot of its energy trying to fill out long canes with leaves it may not be as well off as if the canes are shorter and its allowed to get bushier. Just my suggestion. Roses are fast growers and can leaf out rather quickly during the growing season so I would prune them (maybe not a hard prune but a light to medium pruning leaving as many leaves as possible). And like someone said above, spray spray spray even in the rain you're better off with some spray than none at all. Once the rains stop (for a few days at least) you should start getting some good growth. Use a fast liquid fertilizer to get them back up on their feet quickly (miracle grow or similar). And take note of the ones that suffered the most and give them extra winter protection. I don't think there is any need to shovel prune them if this is the only time they have had this problem and the weather is out of whack. Especially if they have performed well for you in the past. If not then its something to think about. But you don't have to be so quick to shovel prune. Roses, like any other living thing get sick, but they can get better. :)
    (if they are always sickly then that's another story).
    Good luck!

  • dublinbay z6 (KS)
    10 years ago

    It's rather late to give advice to the original poster (who posted in 2009!), but since this thread has been called up again, let me just add my experience with Double Delight--my most BS prone rose in my garden.

    We've had continual rains here also--which means more BS than usual. Predictably, DD came down with a major BS attack. On a dry day, I sprayed it with the Bayer fungicide. Then I pruned it back a bit more than usual--but not drastic pruning, but a bit more. I was hoping the pruning would stimulate DD to put out new canes and other growth. Then, because I had no alfalfa cubes on the property, I got out my Plant-Tone which contains alfalfa (plus some other goodies) and generously spread it around the base of the plant and watered it in. Then I went off and did other things for a week or two instead of hovering over the plant.

    Checked Double Delight out yesterday--it has so much new growth that I can hardly believe it. New canes from the soil line (I bury my grafts), strong growth along the old canes, red leaves everywhere. It's looking better than it did at the beginning of the season after its early spring pruning/feeding.

    I don't know which of those things produced the "magical" transformation of my DD--the continual rain probably helped since it has not really been heavy rain--just continual. I personally think it was the combination of pruning a bit heavier than usual plus Plant-Tone with alfalfa in it that made the difference.

    DD has so much heavy, beautiful new growth on it that I snuck in a preventative fungicide spray of all those red leaves. Normally I don't spray ahead of time--but I didn't want to lose that wonderful new growth this time--cuz it is still raining almost every day here!

    Kate

  • SoFL Rose z10
    10 years ago

    Dublin, I'm so glad you posted this because that's the exact reaction I would expect a rose to have and therefore the advice I gave above. (Sorry, I revived this old thread because I felt the question was a good topic, what to do once BS has had its way with a rose). I live in a frost free climate and since I don't have the winter to let my roses go dormant and prune I do my pruning when roses in my garden become lanky and defoliated. I just prune it, give it some fertilizer (rose tone is great) and they bounce right back with more foliage and more flowers. Yes you get a smaller plant for the season perhaps and there will be a longer wait for blooms, but over all you'll get better health/blooms and the plant should be stronger come winter than if you left it long and lanky with no leaves to try and support itself. :)
    PS my Double Delight is also the MOST BS ridden rose in my garden. But love those blooms!