Shop Products
Houzz Logo Print
ellen_portland

Black Spot on roses

ellen_portland
9 years ago

Hi,

Every year my rose bushes look great, happy and healthy at the beginning of Spring and now have yellow leaves and black spot. How can I keep this from happening?

Comments (20)

  • Embothrium
    9 years ago

    Replace with resistant cultivars.

  • ellen_portland
    Original Author
    9 years ago

    Not financially doable in any way.

  • gardengal48 (PNW Z8/9)
    9 years ago

    Remove the most affected foliage and clean up around the plants as thoroughly as possible. Apply neem oil alternating with Cornell mix on a weekly to 10 day schedule throughout the season, beginning before you see any symptoms. Most fungicides are only prophylactic, not curative, so the best you can expect is to keep new, unaffected foliage clean of disease. Alternating between the two fungicides (both of which are considered natural or 'organic') will reduce the chances of the fungal pathogens becoming resistant.

    It's not the be-all and end-all to rose diseases but it will help. And fwiw, in our climate there is really no such thing as a disease resistant rose - they can ALL get problems.

  • jean001a
    9 years ago

    Put it this way: In our climate, they all WILL have problems.

  • charleney
    9 years ago

    I use (with total success) Bayer Advanced Disease Control. Now READ Carefully!!! Nothing else in it but the disease control. It is not all that expensive at all, when you consider it is a concentrate. FOLLOW DIRECTIONS!! IT WORKS! I had a hard time finding it. Lowe's has it!

  • ellen_portland
    Original Author
    9 years ago

    Thanks everyone. Much appreciated. I have a big, goofy Golden Retriever so I have to be careful.

  • mikebotann
    9 years ago

    I have a Rosa rugosa, 'Glauca' that's doing OK. Other than that, I don't grow them. Too much of a hassle that I'm not willing to put up with. Fungus, thorns, hard to weed around, and they're deer candy. No Fall color and horrible branching pattern. Branches are hard to compost too. Oh, and I can't seem to prune them without drawing blood sooner or later. That's another plant I'll enjoy in someone else's garden.
    Blooms are nice though, but not enough to sway me in to growing them.
    Mike

  • OregonGrape
    9 years ago

    I've given up on the Rosaceae family. I had similar problems with a Sorbus sitchensis years ago, and the fungal rust on my Amelanchier alnifolia was so bad this year that I tore it out of the ground. I'm not going to waste my time babying these plants with fungicides when there are plenty of other disease-resistant shrubs that look just as good and grow just as well in our climate.

  • Embothrium
    9 years ago

    I've grown varying assortments of dozens of kinds of roses for many years without deal-breaking levels of disease. And you can equal the cost of new plants of resistant varieties pretty fast buying and spraying chemicals.

    The service-berry rust comes and goes. The collection of them I have on Camano Island was suddenly full of it one year and the next it was nearly gone, pretty much haven't seen it there since.

    There isn't a Rosa rugosa 'Glauca', maybe you are talking about red-leaf rose (R. glauca). Unlike R. rugosa this often gets some spotting of the leaves, and is also prone to blackening and shriveling of the fruits.

    Pure, non-hybrid rugosa roses are pretty much cast iron. In fact, they don't like to be sprayed.

  • OregonGrape
    9 years ago

    Serviceberry rust seems to be worse when we have unusually warm springs and our usual level of moisture. It wasn't that bad last spring, when it was unusually dry. I clipped off about a dozen leaves and it looked great. This year, when the rainfall was approximately normal and we were in the mid-70s in March, it covered about 80% of the plant, including many of the new stems.

    It seems to me that serviceberry would be better for the garden in areas where it's either cooler (Seattle) or drier (Medford) in the spring.

  • Embothrium
    9 years ago

    Native species is generally distributed throughout the West, I have seen thousands of specimens in flower recently from Island County to Chelan County in WA and down to Portland without noticing anything much in the way of disease.

    Maybe a few problems here and there that have not made a lasting impression.

    It tending to be cleaner of leaf than the eastern North American species is one of the things you notice about Amelanchier alnifolia.

  • OregonGrape
    9 years ago

    There are multiple subspecies/forms native to OR (and presumably WA). My guess is that the interior plants do not handle high rainfall and clay as well as the ones native to the I-5 corridor. I was probably sold one of these interior forms.

  • Embothrium
    9 years ago

    Could be. I saw some stock at a garden center here yesterday that had a little orange spotting here and there. The leaves were more of the oblong shape, like those of 'Regent' (but the plants were labeled as the typical species).

    Or the species in general gets some rust now and then, just not usually the heavy infestations that sometimes blight the eastern species.

    One time in Whatcom County I saw a large patch of what was probably Rosa pisocarpa in a field at a park where there was a lot of rust in one corner of the colony while the rest of it looked fine. The start of an infestation that was going to spread, or a susceptible individual among a larger area of resistant growth?

    The thing about the second hypothesis is that the rust was all over the one part yet had not appeared much, if at all on any of the rest of it - as far as I could see driving slowly by.

  • mikebotann
    9 years ago

    Ron, here's a picture of the rose I'm growing. It has leaves that are sort of blue. Picture taken yesterday. Any chance of an ID without a bloom?
    Mike

  • mikebotann
    9 years ago

    Another picture.
    Mike

  • Embothrium
    9 years ago

    Rosa glauca.

  • mikebotann
    9 years ago

    Thanks bboy!
    I knew it had glauca somewhere in the name. ;-)
    Mike

  • thyagu
    9 years ago

    I am new to this forum, I have a problem, My rose plant leaves is having patches of black color. I dont know where to ask about this and what is the cure for it. Kindly help.

    regards,

    Thyagarajan Shanmughan

  • blheron
    9 years ago

    I love roses and have had them for over 40 years. But, I pretty much gave up on them. The maintenance to keep the aphids and black spot under control was just too much. I bought them from JP and they are still fighting to make it after all these years with only pruning.

    Last summer I purchased Bayer "All in One" (?) liquid concentrate. It was supposed to take care of insects, black spot/fungus, and fertilize. Unbelievable! My roses looked like the first year I planted them. So of course I went out and bought several more roses. BIG mistake. I used the Bayer, but had thick aphid colonies and leafless plants from black spot on all the new ones, and the old ones are now reacting the same way.

    I called Bayer and they were very condescending and tried to put it all on me. (I followed the directions exactly) Only suggestion from them was to do an additional treatment--but ONLY one. Didn't help. BTW, they are planted in two different locations, miles apart.

    Gave it another try this year, now it's in granular form, and see no difference. I just want to toss them all, but I love them all, and a big investment. The new roses are supposed to be disease resistant. I guess I'm just not supposed to have roses :o( .

    Charleney--has the "Bayer Advanced Disease Control" continued to work on the black spot over time?

    Am I doomed to have leafless roses with misshapen, aphid eaten flowers? Doesn't sound like many have had much success.

    Sorry to go on, but needed a shoulder to sob on. I'd welcome *any* suggestions....

    Linda

  • charleney
    9 years ago

    Hi BLheron! YES...But follow directions and maybe spray twice in the wet Northwest. The Bayer Advance works very well for me. You will see more spots appear right after spraying because those leave are infected already. I would also suggest you ask on the Rose Forum site. I think there is a lot of agreement. I also, love the roses and that works well for me. I have been told that fungicides are fairly innocuous, but I am not a scientist. My roses are beautiful, and all I use on them is the BADC,horse manure, and alfalfa pellets. They are easy to maintain, and I have many Austins and hybrid teas, and floribundas. The rose forum people, are also very sharing with their experiences.

Sponsored
Pristine Acres
Average rating: 5 out of 5 stars46 Reviews
Leading Northern Virginia Deck/Patio Specialist- 10X Best of Houzz!