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Disease of New Dawn

Posted by ranyu2011 none (My Page) on
Tue, Aug 5, 14 at 10:48

Hi ,

I'm a beginner of planting rose and I'm having some problems for a while.

This is a New Dawn from David Austin which I planted 1 month ago. At the beginning it grows very well, but after a heavy rain, I found many dark spots on new leaves and buds. Some leaves are even twisted and look weird. (but old leaves are fine)

I searched from books and rose forums, I thought it might be black spot, but I'm not sure. Because it seems that black spot doesn't appear on new leaves? Or it might be pest like thrips? But I didn't find any bugs there.

My other roses like Wollerton old hall, Wisley 2008 also have the same problem. I tried to spray several times but it didn't work.

Now I'm really confused, can anyone tell me what the problem is?

Thanks.

(sorry for my poor English)


Follow-Up Postings:

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RE: Disease of New Dawn

Ranyu, can you take some pictures of leaves with the black spots--maybe even a couple close-ups? I can't really see anything wrong in the picture above. It looks like you just need to be patient and let the rose settle in and grow some good roots. Different roses grow at different rates.

When you sprayed the leaves for what you thought was blackspot, what spray did you use? Some sprays are much more effective than other sprays.

Kate


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RE: Disease of New Dawn

Thank you very much for answering!
I just took another picture of my rose , now the problem is more clear I hope.
Maybe I'm too looking forward to see the flowers, so I'm really worried about the disease before it blooms.:)


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RE: Disease of New Dawn

This is the spray I used.
I live in UK, it seems that it's the only spray for rose I can find here.What do you recommend?


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RE: Disease of New Dawn

Another picture.
sorry I don't know how to post several pictures in one message.


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RE: Disease of New Dawn

Are we talking about the brown spots visible in the lowest image above? Or the purple leaves in the top picture? Are the brown spots sunken? Hate to be a nuisance, but the camera is not sharply focused on the spots. We need to see the definition at the edge of the spots clearly. Could you try again? Also could you list the active ingredients in Rose Clear? Thanks.

Doesn't look like a severe problem but we should try to diagnose.

One thing I can say about the product is that we don't recommend combination pesticide products. I use a fungicide routinely but do not need an insecticide, so it would be harmful to apply one routinely.

This post was edited by michaelg on Tue, Aug 5, 14 at 16:51


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RE: Disease of New Dawn

I don't know what is causing those brown spots, but I'm pretty sure it is not blackspot.

Michaelg may have other thoughts (he's good on these diagnoses things), but I'm still thinking you are just being overly anxious and worrying too much about your "babies." As long as they are getting plenty of sunshine (at least 6 hours) and regular watering, I'd leave the rose alone to do its own thing in its own time. And if those speckled leaves bothered me and there aren't too many of them, I'd probably just trim them off--then everything would look nice. : )

Michael may have some good advice, however. So far, I agree with everything he has said.

The reason you can only post one picture per post is because that is the way GW set up this forum. For multiple pics in one post, you have to upload your pics to a free online source--like photobucket.com--and then copy the HTML CODE they provide and paste it in the message box here at GW. You can insert as many HTML CODES as you wish.

Kate


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RE: Disease of New Dawn

  • Posted by subk3 7a/MidTn (My Page) on
    Tue, Aug 5, 14 at 18:42

ranyu2011, I live in the American Southeast which is an area of the county with a great deal of disease pressure and grow New Dawn. This rose has a reputation for being disease resistant, but it is probably the worst rose I have--I successfully grow mostly old Tea roses and some very modern roses bred to be disease resistant. New Dawn blackspots heavily for me but doesn't loose a lot of leaves. It is just ugly, but it might be better for your climate!

I think a couple decades ago a rose that kept its leaves through diseases was about as good as a "modern" rose of that time frame would do. Were it being bred today I don't know that it would be so highly recommended for disease resistance.

I think some of the older Austins might be the same. Disease resistant compared to other current selections but maybe not so great compared to what's available now. I have not had good results with Austins here either.

I know your choice of chemicals in the UK is much more limited that what we have available here. So maybe more research for more modern roses that are disease free would be helpful.

As far as blooming this year you will have to be patient. My New Dawn has very limited re-bloom after the flush. If this is a very young rose you would probably be better off nursing it for root development by disbudding any buds and waiting until next year for blooms. I know!! Easy to say, hard to do!

Good luck!!


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RE: Disease of New Dawn

Not an expert, but I do have a New Dawn and it's sport Awakening. I live in an area where disease pressure (mostly blackspot) is very high, but New Dawn is one of the roses that are not affected much. It is also extremely vigorous too. My guess is that you don't need to spray at all for this one: they might have imperfect foliage from time to time, but it should be tough enough to do with any cuddling from you.

Be forewarned: your ND might turns into a out-of-control monster before you know it. Mine 4-year old ND wants to eat the house. And the big thorns! :)

Good luck!


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RE: Disease of New Dawn

Thank you all, I’m impressed with the warm and professional answers!:)

I just woke up, took advantage of sunny daylight to take some pictures. Hope this time it’ better and Michaelg can give me some idea about what it is.
I'm talking about the brown spots in the 2 pictures below.(the spots are sunken. )

The Rose Clear which I used contains:
0.15 g/l Triticonazole and 0.05 g/l Acetamiprid as a ready to use micro-emulsion formulation.

rose2
rose1

Kate, thank you for your advice, I'll try not to focus too much on my "baby".:) My last rose is “breath of life" , I can't ignore the spots and ugly leaves, so I trim them so much that after one year it still doesn't bloom at all...:(
This time I think I will be patient.

And thank you for teaching me how to post pictures.

This post was edited by ranyu2011 on Wed, Aug 6, 14 at 7:38


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RE: Disease of New Dawn

subk3,

I did some research about New Dawn before planting, I did hear that it's not so healthy. But the pictures of Austin Rose are so breath taking, and each one is described as "hardy" and "disease resistant" , and the weather in UK is good for rose.....so, I decided to give me a chance......

Until now, I found I'm too naive, all the DA roses I bought have been sick without stop. The only exception is "Parade". So far it's still perfectly strong without any sign of disease.

Thank you for your advice, next time I'll try some other modern roses that are disease free like you said.

farmerduck,

I heard that New Dawn is a monster which will eat house ....hahaha, so I prepared a big fence for it, do you think it's enough for New Dawn to grow? :)

rose3


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RE: Disease of New Dawn

If the picture is not clearly enough, you can click it to have a bigger size. :)


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RE: Disease of New Dawn

Thanks for the good information. I have seen the brown sunken spots on certain roses including 'Cherry Meidiland' and 'Pink Grootendorst'. It looks like the anthracnose spots that develop on mangoes and papayas I don't know. It is not that common on roses and does not appear in the Compendium of Rose Diseases. The fungicide you are using may or may not control it. If it has continued to spread after you began spraying, the answer is obviously "no." It will not kill your rose but might make it look messy. Like all fungal diseases, it will spread only under certain weather conditions.

'New Dawn' is a tough rose, generally disease resistant, and should not require regular spraying. subk3's experience is not typical. Ideally, it would get a bigger fence, but you can grow it there. Fan the canes nearly horizontally, whack it as necessary, and go easy on the fertilizer.

I looked up your chemicals. Triticonazole is effective against the main rose diseases, blackspot, rose rust, and powdery mildew. It seems less hazardous than the older synthetic fungicides, but 'New Dawn' probably doesn't need it. You probably don't need the insecticide either. Don't worry if aphids (greenfly) appear in spring--they will go away.


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RE: Disease of New Dawn

Thank you Michael, I really appreciate the advice, very helpful. Most important thing is, I know it's not a severe problem through your answers, that's good enough to me. :)

I will try to train the canes, it must be the most interesting part of growing climbing rose.


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RE: Disease of New Dawn

Training is not hard if you are armored against thorns. Get some gauntlet gloves made for rosing or for welding. Don't worry about training the shrubby growth that you now have. Strong shoots will appear at the base and grow maybe 8 feet--later shoots maybe 12 feet. Let the shoot go until it is grown out and fibrous rather than brittle--maybe it will bloom at the end. Then promptly bend it over all at once in a shallow arc and tie it down. Don't try to guide it while it is just starting along.

The bent canes will bloom all over in the spring. After blooming, cut the short blooming laterals back to 2 leaves. Don't let big hips develop. Beginning in March 2018, remove 1/3 of the oldest canes at the base each spring. This will keep the plant young and help control the size.


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RE: Disease of New Dawn

wow……2018~~seems very far from now. :) You have given me such a long plan, that's amazing!
I think I should save these advice as wallpaper in case I forget.

Again thank you very much
Now I know what I should do with my roses.:)


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RE: Disease of New Dawn

Second thought--some people do the annual rejuvenation pruning at the end of June in order to maximize the spring flush of bloom. Either way is fine.

Also, you can start that in 2017 if you have a lot of canes by then.

Good luck and send us a picture once it is established and blooming a lot.


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RE: Disease of New Dawn

  • Posted by elks US5 Can6 (My Page) on
    Sat, Aug 9, 14 at 7:01

It is not unusual for a climber to take 4 years to really take off, but you will be rewarded.

Steve


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RE: Disease of New Dawn

I planted climbing roses for the first time this year and Paul Zimmermans videos how to train a climbing rose are very helpful. You can view them on YouTube. I am a visual person and it helped me to see how it was done. Good luck!


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RE: Disease of New Dawn

About training New Dawn: I have given up trying as the canes are stiff and the thing is a thorny monster. As soon as I ties one cane down, another one shoots right up. But I am a newbie (and a untidy gardener), and for the record, I did see Awakening beautifully trained. I doubt I would ever acquire that skill (or have the needed desire/courage). I don't get too close to ND these days, and have given up dead heading it.


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RE: Disease of New Dawn

I'm not a bug expert, but I'm not a rose newbie and I am sure those spots are not fungus, but made by some kind of insect sucking sap of new growth or munching away at the leaves in odd ways. There are loads of them, not just aphids and larvae, there's a group of insects called heteroptera that cause exactly the type of damage your roses have in these pictures. They suck or eat on the tender new growth, and as the leaves continue to grow the damage show up as spots, deformed, curled up leaves, tiny holes, etc. You can't really prevent it, but you can spray some kind of insecticide if there are lots of this. Heteroptera insects aren't as easily detected as aphids and larvae, because they don't stay on the leaves and on the plant that much. When they are finished eating, they will wander off to a near by plant, perhaps come back later in the day, or next day. The make noticeable damage to new growth even if they dont come in huge numbers like aphids and larvae. You might have a few of them and they make their presence know if the decide to stick around.


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