Roses forum: Help with roses before winterizing

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Name: Michele Miller
Sandusky, Michigan (Zone 5b)
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Michelezie
Sep 21, 2017 9:46 AM CST
I've got 5 hybrid tea roses that had just about every problem under the sun this season. 4 of them I just transplanted this spring. The Japanese Beatles ate practically all of my buds. Then I had these green caterpillars strip two of my rose plants clean of most of their leaves. And now I'm noticing what looks like black spot. I fertilized with Bayer all in one rose & flower care twice after transplanting. Then used an insecticide/fungicide soap spray once I noticed the black spot starting. I did my best to hand pick the beetles and caterpillars. Then tried pruning away damaged foliage. I'm hoping to give them a better start for next year. Should I do something to treat them for black spot before I cover them for winter? I'm hoping to get some pictures later today.
Name: Steve
Prescott, AZ (Zone 7b)
Region: Southwest Gardening Roses Irises Lilies
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Steve812
Sep 21, 2017 5:24 PM CST
I'm sorry to hear about your difficulties with HT roses, Michelle. I've lived in the northeast and struggled with all those problems. And even here in zone 7B, I lose some HT roses to late spring frosts.

Can you tell us which HT roses they are, Michelle? Certain cultivars definitely need some kind of winterizing, others may not.
Name: Michele Miller
Sandusky, Michigan (Zone 5b)
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Michelezie
Oct 8, 2017 9:59 AM CST
I have Apricots n cream, best kept secret, koelner karneval, Memorial Day, and Traviata.

Is there anything I should spray them with to try and prevent black spot for next year?

I'll try to get a picture today. I've been putting it off because I need to weed the bed.

Thanks for your help and sorry for the delayed response!
Name: Steve
Prescott, AZ (Zone 7b)
Region: Southwest Gardening Roses Irises Lilies
Image
Steve812
Oct 8, 2017 10:46 AM CST
I use the fungicide Actinovate SP to help prevent fungal infections blackspot, downy mildew, and powdery mildew. I cannot claim perfect success with it; but I am sometimes both reckless and stingy in using it. When I am very focussed and organized the stuff works, mostly. I would spray the canes right now (wear a respirator, just in case), before piling one or two feet of mulch around them, then immediately after pruning and uncovering in the spring. And I'd spray the soil around the rose for a distance of about two feet out from the trunk. In spring I'd repeat every two weeks until some fungus appears, at which point I would read the label directions and follow them very carefully. Rolling my eyes.

I have had some limited success with Milky Spore to treat Japanese beetles; I do recommend wearing a respirator while spreading it so you don't inhale too much of the stuff. It can take a year or two for it to work. And some people tell me that it has to be used at least every other year to be effective. Still, I have noticed that it does reduce the JB damage, even if used on a suburban lot a little smaller than 1/3 of an acre.

I've not grown any of those cultivars, so I can't give any cultivar-specific info, but I expect that most of those roses will benefit from some mulching to prevent late frost damage. Not sure when to pull back the mulch. My guess is that by mid May it would be safe, but maybe one (a person in New England, for example,) could do it as much as two or three weeks earlier.

Good Luck with your roses!

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