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zone5rose

how to prune rust-afflicted alba maxima?

13 years ago

My alba maxima has a beautiful form and is healthy apart from getting rust badly some years. This is one of them and I think I have put companion plants too thick around her. I've gotten rid of some of these and will spray with some organic stuff, but how much should I prune out in an effort to help her along? I'm guessing air circulation is part of the problem--none of my other roses do this. It's a sad business. Thanks, Zone5rose

Comments (5)

  • 13 years ago

    No one closer to your zone has answered yet?

    What I do with bad Rust here is just cut off ALL the affected leaves and give the plant a small dose of fast-acting fertilizer to help it leaf out again quickly And it doesn't hurt to throw the diseased leaves out with the trash.

  • 13 years ago

    Alba Maxima and Alba Semi-Plena are my favorite Alba roses and their beautiful foliage makes them very desireable garden plants, in my opinion.
    Although Alba roses are generally considered to have
    "bullet proof" foliage some gardenweb members, including myself, have noticed a bright orange rust on Alba Maxima and Alba Semi-Plena.
    My Alba Semi-Plena, had, one year, a rust quite different from that which was on one of my H.P.s, the Alba rust appeared like "Cheetoh"s, and was a vivid bright orange color, and appeared in thick almost tubular shape.

    Here's what I did:
    -removed all infected leaves.
    - check the undersides of all the leaves because rust hides there and can spread if the leaves arn't removed.
    -prune off canes that were badly infected, and just before I got down to the clean cane area, soak the clippers in vinegar, for 5 minutes, to kill any rust spores on them and wipe clean and dry.

    After my plant was clean of rusty leaves, then I sprayed the entire plant, and was careful to
    -spray the undersides of all the leaves.
    -sprayed all the canes and twigs, in case a few rust spores fell from the leaves onto them.
    The next year only 4 or 5 leaflets showed light rust, and I never needed to spray it again.
    I myself, wouldn't bother moving companion plants yet, but wait until next year, to see if spraying alone will solve the problem, however my rose companion plants only come up to c. 1/5th or less of the total height of the rosebushes they're near, so that air flow is not impeded.
    I used a double dose of baking soda in the Cornell spray, which makes the leaves too alkaline for rust to thrive. It left a powdery film that I ignored, because it took care of the rust. Unlike powdery mildew extra strength Cornell does not make the leaflets shrivel, so you can tell its' not p.m..

    Extra strength Cornell Spray

    2 tsp. baking soda
    1 tsp Canola oil
    1 quart water.

    Good luck,
    Luxrosa

    P.S. F.Y.I., If rain washes off the spray, re-spray through the growing season as needed.

  • 13 years ago

    Thanks very much, Luxrosa-that cheetoe stuff is exactly right, but now it's given way to generalized yellow rust and what are I guess the black spores on the undersides of the leaves. I had this problem before, but then was free of it for two summers. The companion plants--baptisa, lilies, shasta daisies, sage, etc. are very close. I like a dense English garden look. I'd post photos, but I can't figure out how to do it! I will prune out a lot and remove as many leaves as I can, but it will be nude!
    bummer
    zone5rose

  • 13 years ago

    I wouldn't blame your companion plants too much. I have the (orange cheetos-type) rust problem on two albas, Maxima and Semi-plena and they are out in the open air with just about as much air circulation as you could get. In fact, that was my first thought - that with their long arching canes they catch the rust spores in the prevailing winds. The first year it ocurred, Semi-plena was absolutely covered in it and I sprayed. This is the fourth year and there is some rust, but not so much - which is lucky for me because I don't spray anymore. Like others above, I pick off the infected parts. I've read that some Albas are just prone to rust and it doesn't seem to be spreading through the garden so I'm not worrying about it.

  • 13 years ago

    Yes, they're getting rust because of what they are - not because of what is growing with them. Spray for the rust or try reducing it with fertilization*, without whacking them back or picking the leaves off: how does this decapitation/denuding improve things for the bushes over merely having some rust?

    *Supposedly connected to phosphorus deficiency, although I would be careful about pouring on P as this can produce a toxicity to the plants that is hard to remove without digging and replacing the treated soil

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