Blackspot overwintered I guess.....need advice

7 years ago

I'm in eastern NC - my roses are in their second year, from bare root last year and fully out, starting to form buds, climbing, etc. I have multiple leaves on almost all bushes with black spot. Trying to remove all the leaves is difficult because they seem to be from overwintering and in different stages of development. I've attached some pics and need advice for what to spray at this early stage of growth to kill this blackspot! Blackspot was not a problem last year - but it has always been a problem in this area in the past. Thank you all -

Denise in NC

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Comments (5)

Moses, Pittsburgh, W. PA., zone 5/6, USA
7 years ago
last modified: 7 years ago
Every year is different for black spot. New strains pop up that your roses don't have a resistance to. Weather conditions favor black spot some years, and work against black spot other years. You have to be prepared for all possibilities.

I advise you to start a spray program. Bayer makes an excellent fungicide for roses. Going organic, you could try the neem oil types or the good bacteria formula called Serenade. With Bayer you only have to spray the leaf surfaces every week at first and stretched out to every two weeks after a few sprays. With Serenade both leaf sides must be sprayed, applied more frequently, especially after a rain. The level of good bacteria must be maintained at a minimum to work. The good bacteria washes off easily, unfortunatrely.

Black spot pressure is a constant given here and spray I must or limit myself to a narrow selection of black spot resistant, blah roses. Very few fragrant roses are black spot resistant here.
Denise Hall thanked Moses, Pittsburgh, W. PA., zone 5/6, USA
Denise Hall
Original Author
7 years ago
Moses,

I'm feeling better about what I have done so far - thanks for your advice.

At mid February when I cut back the roses and mulched heavily I added Bayer 3 in one to the dirt under the mulch and worked it in well.

I sprayed with Neem oil a week ago after seeing the blackspot - thinking that too much Bayer/etc would be overkill for right now.

I just sprayed again with Neem during the last hour. We are due a thunderstorm and some rain tomorrow so it will probably get washed off.

I would love to be able to use the good bacteria - especially preventively - if it will just work.

the aphids are already here - I saw them under a microscope just before I decided to respray the Neem! Not too many - on the underside of the leaves here and there - but without spraying - tomorrow they will be feasting on all the buds!

Thanks for your input - I also have been reading through the thrip/spider mites/midge thread - last year I "think" I had midges in one area - my round garden of Drift roses. I did conquer them with Spectricide spray - hated using it!!

Denise
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I'm in colder zone and grow two on your list, The Squire and Radio Times. Tradescent, I have shovel pruned, too weak a grower in a cold climate and very disease prone, the flowers were perfection though few in number with poor repeat. I also shovel pruned Molineaux because it was far too tender in my climate and struggled to grow and perform. Might be ok in a zone 6 climate though. The Squire is a bit of a Diva. I grow him in a pot and he winters indoors. He is a moderately vigorous grower in my climate, but stays small, has sparse foliage and gets moderate blackspot, always. I grow him because of the perfect old fashioned scarlet blooms. There are always a few, though there is no fragrance. But this is a collector rose, not for those who don't like fussy divas. Radio Times is cold hardy, vigorous, thorny, blooms reasonably well, has gorgeous blooms with superb old rose fragrance, but is a black spot magnet. Another rose I keep because of the gorgeous blooms and fragrance, even though it can defoliate. Interesting that you mention Darcey Bussell, I grow both DB and Munstead Wood. Got them both last year and both wintered indoors in pots. Of the two, Darcey Bussell was the better performer in year one. She was more vigorous, disease free and bloomed well. Munstead Wood, while growing and blooming well in early season, succumbed to the local strain of Blackspot and defoliated completely. Having said that, I often find that certain roses will Blackspot badly and then seem to acquire immunity, so I will see how MW does this season with respect to disease before I contemplate removing him. My two bits for what they are worth. Cheers, Rick
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He disagrees with the experts?? everything he does listed in this article is part of the local dogma about growing roses, adhered to by most of the rose societies in the area. I'm the heretic, here in Olympia, for not stripping or mulching. Every fall my fellow rosarians gasp in horror and tell me all my roses are going to die, and every spring I have less winter damage than they do. Last fall we stripped and mulched the society garden in early October!! That was too too much for me. I'll help in November, even though it's not something I do to my own garden. But not that early. But they're convinced that stripping and mulching are absolutely necessary. It's the dogma of rose culture around here. So this guy is mainstream. Sure, the leaves can carry over blackspot spores, but getting rid of the leaves won't get rid of all the blackspot spores. Blackspot infects the canes too, so there are plenty spores overwintering in those dark spots on the canes. You'd have to prune all the canes off right down to the ground, and then remove the surface soil, in fall to get rid of all the spores. Then more would blow in in spring, plus you'd now get crown gall on your canes from pruning at soil level. I wonder who told the writer that this guy disagrees with the experts. Bet the writer doesn't grow roses.
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I have found that using whole ground cornmeal works the best for blackspot. You can buy it at nurserys and at feed stores. Take a handful or two, and dump it under the rose, close to the stem, about out to the drip line. Water it in. The water activates the chemical process that cures the blackspot. You can use this ad lib. I also feed my roses with epsom salts and granulated molasses. You can get the epsom salts anywhere and the molasses can be obtained at a nursery or feed store. The new leaves that come out will not have the blackspot. There isn't anything you can do about the old leaves except pull them off. Be sure and put them in the trash can, not on the ground. Also, you can help prevent the blackspot by watering in the morning, water the roots and try to keep water off of the leaves. Watering at night, getting water on the leaves seems to aggravate the condition. Good luck. Cecelia
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Dingo2001 - Z5 Chicagoland
7 years ago
Are those the leaves leftover from last year? I think you warm zone folks remove those usually? One thing we don't deal with in the cold :) but I know by the end of the summer the leaves start looking pretty rough, even if they were clean all season.
Denise Hall
Original Author
7 years ago
Some of the leaves from last year are still there- yes - but most are new. I didn't remove leaves from last year though - unless they were damaged, half falling off. I will remember to take all the leaves off next year before February though - thank you!!!
Moses, Pittsburgh, W. PA., zone 5/6, USA
7 years ago
It's worth giving Serenade a try, Denise. I plan to give it a trial on only a group of Deja Blu in my rose bed. They are black spot magnets, but bloom their heads off, and have a strong scent. If it works on them then in the future, I will proceed to see how Serenade will work as my only fungicide.
Denise Hall thanked Moses, Pittsburgh, W. PA., zone 5/6, USA

Blackspot overwintered I guess.....need advice

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Moses, Pittsburgh, W. PA., zone 5/6, USA

Denise Hall
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Blackspot overwintered I guess.....need advice

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Moses, Pittsburgh, W. PA., zone 5/6, USA

Denise HallOriginal Author

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