Roses forum: Black spot

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Name: Zuzu
Northern California (Zone 9a)
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zuzu
Feb 7, 2010 2:58 AM CST

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This forum needs a good start, and black spot is probably the bane of every rose gardener.

I actually might be the wrong person to start this thread because I do nothing whatsoever to control black spot. Through the years I've tried various things, but they've never worked, and life's too short...

It seems to me that black spot is inevitable unless you live in a climate dry enough to be described as arid.

Yes, it makes the leaves ugly, but it can't kill the rose and it doesn't affect the blooms, and they're the important thing to me. Besides, the leaves eventually fall off and are replaced by beautiful new and healthy leaves.

I have about 1500 rose bushes, and almost all of them get black spot -- even the ones that aren't supposed to, such as Knockout. I have two roses that stand out from the rest as far as disease resistance is concerned: Playboy and Cinco de Mayo. There are others, but those two are conspicuously free of black spot because they're surrounded by other roses that are plagued by it.

I've also found that roses grafted onto Multiflora rootstock are generally more resistant to black spot than own-root roses and roses grafted onto Fortuniana or Dr. Huey rootstock.

Here's a picture of Playboy just to dress up the thread.

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Name: Toni
Denver Metro (Zone 5a)
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Skiekitty
Feb 7, 2010 10:11 AM CST
2009 was the first year I (and other gardners here) had had blackspot. And it's a pain in the butt! It's not fun at all and it does make the plant look gross. And we had slugs, too!! That's a total first.. I haven't seen slugs since I moved to Colorado in '01!! I used GreenLight to control the blackspot.. it worked pretty good! :)

Here's Gingersnap only 'cuz I love Gingersnap. :)

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Name: Teri
Mount Bethel, PA
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Roses_R_Red
Feb 8, 2010 6:37 PM CST
We had cloudy weather and rain most of last summer so that the black spot was out of control. By August almost all the leaves were gone from the bushes and it looked like they had about had it. I did cut many of them back because they were producing nothing. All this time I had been spraying like crazy.

September brought a few dry sunny weeks and the rose started to send up their new red shoots and proceeded to give us a good show for a short while. Hopefully the weak looking bushes will have enough strength to get thru this exceptionally cold winter. I'm happy about the snow because I think it helps to protect against the frigid whipping winds.

I will repot my sad looking miniatures first thing tomorrow Zuzu. I have some potted rose bushes in my house overwintering because they looked so scrawny when I got them on sale last fall. They are doing fine, but of course I used all my own products to pot them up.
Name: Zuzu
Northern California (Zone 9a)
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zuzu
Feb 8, 2010 11:00 PM CST

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It's so awful when all the leaves fall off in the middle of summer, just when things should be looking great, but it happens, and it actually looks better than when those black leaves hang on to the bush. I sometimes hit the bushes with the jet-spray attachment on the hose to knock all those awful leaves off. The next set of leaves is always beautiful.
Name: Teri
Mount Bethel, PA
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Roses_R_Red
Mar 22, 2010 9:20 AM CST
I'll try the jet spray instead of totally cutting them back if it should start again.
Name: Clint Brown
Medina, TN (Zone 7b)
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clintbrown
Mar 23, 2010 4:37 PM CST
That Playboy rose looks like a beauty! I'm glad to hear about Cinco de Mayo. I bought several of them this year and it will be nice not having to worry about the leaves falling everywhere.

I had good luck using Daconcil spray on my roses last year. My Evelyn Rose didn't get black spot last year at all and it always gets black spot!
Name: Teri
Mount Bethel, PA
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Roses_R_Red
Mar 24, 2010 5:53 AM CST
Zuzu,

I meant to tell you that until I read your first post, I never knew that black spot would NOT kill the rose bush!!
Name: steph mueller
san diego
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stephgem
Apr 11, 2010 7:53 PM CST
I hate black spot too. I do the same thing though hit them with the jet blast of water and they fall offf...

Holy smokes 1500 roses. I would be eat drinking and breathing roses.....
*****huggs******
steph
Name: Zuzu
Northern California (Zone 9a)
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zuzu
Apr 17, 2010 8:10 PM CST

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This week my garden looks like a black spot plantation. You'd think I was growing the stuff for big bucks.

So, if you have any questions about the black spot-resistance of roses, ask them now. I have way too many to make a list of the ones affected. I might take a stab at making a list of the ones that aren't affected because they're in the minority.
Name: Teri
Mount Bethel, PA
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Roses_R_Red
Apr 18, 2010 4:19 AM CST
Oh no, Zuzu!

I hope that you will not be too bummed out by this, as I was last year.

I once read that the darker ones are more resistant. Are you finding this true?
Name: Zuzu
Northern California (Zone 9a)
Forum moderator Plant Database Moderator Charter ATP Member Region: California Cat Lover Roses
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zuzu
Apr 18, 2010 4:33 AM CST

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Not at all, Teri. It happens every year after the rainy season. The leaves eventually will fall off and lovely new ones will grow. It's just a seasonal thing.

I'll check tomorrow and see whether the darker ones are more resistant. My immediate impulse is to say that they aren't because I remember noticing that Night Time, which is almost black, was one of the saddest looking victims. It might have more to do with the class or the hybridizer. I noticed that the foliage on Marie Curie, for instance, looked absolutely pristine. It's a Meilland shrub, so I'll have to take a look around and see whether the other Meillands or other shrubs look equally good.
Name: Teri
Mount Bethel, PA
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Roses_R_Red
Apr 18, 2010 6:59 AM CST
I'm happy to hear that you have a rainy "season". Our problem last year was that we had a rainy spring and summer. Almost every day. The roses had a difficult looking like anything much until late September. Some of them never got to grow much foliage and those look kind of weak right now.
Name: Zuzu
Northern California (Zone 9a)
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zuzu
Apr 18, 2010 7:12 AM CST

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It rains here from November to April, and we usually don't have a single drop of rainfall the rest of the year. One of my water bills last summer was over $400. It wreaks havoc with my bank account, but at least we have no rain wrecking the rose buds and blooms.
Name: Teri
Mount Bethel, PA
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Roses_R_Red
Apr 18, 2010 7:20 AM CST
We're so fortunate to have well water with always a good supply. Of course, every so often we need to fix the pump, but it's still a bargain.
Name: Steve
Prescott, AZ (Zone 7b)
Region: Southwest Gardening Roses
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Steve812
Apr 18, 2010 11:29 AM CST
Hope I can be forgiven for thinking out loud ...

When I lived in NJ and had been growing roses for five or six years, having been successful with Olympiad and Electron, I got a big shipment of roses from Edmunds. It included Memorial Day, New Zealand, Gemini, Double Delight, Belami, and MAAB. I planted them carefully, scratched organic fertilizer into the surface, and watered regularly. The plants put out leaves and nice shoots in May. And many of the roses made a blossom or two in early June. But by the third week in June all but New Zealand and Memorial Day were completely defoliated from BS. By mid July New Zealand was, too.. Some put out a few token leaves in early September and these persisted until frost in October; but there was never a point in time that season when the roses were lush with healthy foliage.

By the start of the second season three of six MAAB were missing in action. Double Delight was reduced to a 12 inch high pencil thin stick. And Gemini was not far behind. Belami was in similar condition. Though two of three Memorial Day perished due to frost, the fourth came back big and strong, the way I expect roses to perform. New Zealand was slightly diminished, but still bore a decent crop of roses.

I will admit that these roses only got six hours of direct sunlight, but Memorial Day got the most shade, and it did the best because it was completely immune to the problem. I grew Folklore in darker shade, still, and it did not go downhill quite so quickly as these.

In any case, most HTs I grew suffered mightily from the disease. And most of them grew smaller each year until, usually by year three, I removed them. Even the nearby AARS rose garden had trouble keeping Tropicana looking respectable. Those HT's immune to BS - Midas Touch, Electron, Olympiad, and Memorial Day - grew well year after year.

I hazard a guess that on the East Coast, even dry weather is characterized by higher summer temperatures and/or higher relative humidity than is generally the case for your location. In CA, the air has a low dew point during the growing season and if the air is cool enough to be damp, it is generally too cool to promote black spot. In other words, anyone who lives within about 300 miles from the Pacific (and sufficiently far south, perhaps) will not have roses that suffer from black spot the way gardeners in the Midwest, South, and Northeast do. Black spot is one of the reasons I moved west! That and the fact that I cannot tolerate moist air.

It seems to me that if black spot never killed roses, then much of the reason for the fall of J&P and the rise of interest in Buck roses, David Austin roses, and Old Garden roses in places more than 450 miles from the Pacific Ocean goes unexplained.
Name: Zuzu
Northern California (Zone 9a)
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zuzu
Apr 18, 2010 4:06 PM CST

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All right, I've finished my highly unscientific study of black spot. I have to say right away that I do nothing to control it and my gardening practices are almost calculated to cause it. I plant everything close together, water from overhead unless the plants are too tall, and I never pull off the damaged leaves and discard them properly.

Consequently, any rose that doesn't get black spot in my garden is one heck of a performer. I conducted my test with the most rigorous criteria, disqualifying any rose that had even one affected leaf.

I think the results are shocking. Out of more than 1350 different cultivars, only 24 roses were completely free of black spot.

I can only make a few generalizations, largely because of the unscientific nature of this test, but the Bourbons, hybrid perpetuals, and hybrid musks were total duds in the context of BS resistance. The gallicas and moss roses were almost BS-free, but only one of them made the list -- Cardinal Richelieu -- and even that one unfortunately has no pest resistance, so it's by no means the perfect rose. Some of the teas and chinas looked okay and some looked awful.

As far as hybridizers go, the Austins had good resistance, but only 2 of more than a hundred Austins in my garden had no black spot whatsoever. Two of the roses on my list are from the Kordes Fairy Tale series and there are a couple of other Kordes roses there. The Meilland roses looked fairly good, but only a couple made the list. The hybridizer with the very best-looking rose foliage in my garden today was J.B. Williams. Carruth roses also seem to be standouts. The Bucks are not resistant. I have more than a hundred Buck roses and they all have black spot this week.

Only 3 of the 24 on the list are own-root roses. The rest are grafted, about half on Multiflora and half on Dr. Huey.

So, here is my list of roses that don't get black spot in my garden, although they might get it elsewhere.

Cardinal Richelieu, Carefree Delight, Carefree Spirit, Chicago Peace, Colette, Delany Sisters, Festival Fanfare, Gebrueder Grimm, Gertrude Jekyll, Helen Hayes, Jacob's Robe, Judy Garland, Macho Man, Marie Curie, Permanent Wave, Pomponella, Rosenstadt Freising, Royal Bonica, Sisters at Heart, Sunstruck, Super Dorothy, Sutter's Gold, The Charlatan, and The Prince.

It's highly possible, I suppose, that some of these 24 might come down with black spot next week or the week after, but for now they look perfect, especially in comparison with the roses surrounding them.
Name: Zuzu
Northern California (Zone 9a)
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zuzu
Apr 19, 2010 1:52 AM CST

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I went out to work on some things in the garden and saw Colette from a different angle -- the angle from where some black spot was visible. So the list has been whittled down to 23.
Name: aka GardenQuilts
Pocono Mountains, PA
Andi
Apr 19, 2010 10:09 AM CST
I live not far from Roses are Red in the Poconos. I tried all natural methods on my roses last year - neems oil, baking soda and Dawn soap spray biweekly and after rains. The spray made a huge difference in aphids, but I am not sure if it helped blackspot. I also wiped off aphids and Japanese beetles as needed with soapy water, ick. The boys that live nearby had a great time helping me kill the bugs. They thought it was the coolest thing, but I was too nice to be killing bugs -HA.

I still got blackspot, even a bit on Carefree Celebration - a knockoff relative. Austin's Wildeve and Souvenier de la Malmaison had it the worst. They still held most of their leaves, but they looked unsightly. Fire Meilland ground cover rose was closest to the ground, obviously, but had no blackspot at all. That garden patch also got less spraying attention. It frequently was getting dark or I was running out of spray by the time I finished babying the invalids.

The new rose leaves look so beautiful right now that I want them to stay green and shiny. I am going to try systemic fungicides on Eve and Malmaison. I am trying Bayer Advanced All in One Rose and Flower Care. I was mainly looking for imidaclopid in a formula that is poured at the base of the plant, not sprayed. This was the only thing at Lowes that met that criteria. (BTW, it was cheaper at Lowe's than Walmart) I also want to try sulphur, but they didn't have it at Lowes or Walmart, except for a pricey, natural, earthy crunchy dilute preparation which I obviously didn't buy.

I live in a townhome community and have a small cottage garden with as many roses as I can fit, plus. I have been considering moving this year, but haven't found a place enough better to justify the move, especially into another rental. I am too gun shy to buy into this market at this point in time. I dread digging up the garden and replanting but moving the books, fabric and yarn will be even worse!

I haven't been feeling well, so my gardening tasks are behind schedule. I'll get back out there in the afternoon, it is too sunny right now. I have always stayed out of the sun, even with sunblock - which I wear all year long. I just had a thing removed from my back, a basal cell tumor. The doctor got it all, but now I have a divot in my back. There are worse things, I suppose. The bf said , "How did you get skin cancer wearing long sleeves, hats and sunblock?" Who knows, good thing I am not a sun worshiper.
Name: Rita
North Shore, Long Island, NY
Zone 6B
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Newyorkrita
Apr 19, 2010 4:13 PM CST
Last year it rained here constantly (well it seemed like it) all spring, summer and autumn. I never had to water the garden not even once last year. Plus it is hot and humid here in summer.

You have to spray on the east coast with a systemic fungicide or you will get blackspot. Since I hate the looks of blackspotted leaves, or even worse, bare sticks with no leaves, I spray. Always!

I sprayed today again as I am already on my summer spraying schedule. Last year I started much later than this. However, this had been such a warm March that things are way ahead of schedule. For instance, the Azealeas never bloom before the beginning of May and they are just starting to bloom now already. Way early.
Name: aka GardenQuilts
Pocono Mountains, PA
Andi
Apr 19, 2010 9:24 PM CST
Newyorkrita, do you have a favorite systemic fungicide? How often do you spray? I would love my yard to look a beautiful as floribundaville!

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