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Rust on Pelargoniums- Anyone have results with corn meal?

Posted by Braveland4H Zone 5 WI (My Page) on
Wed, Aug 25, 04 at 15:26

I've had a fungus on my pellies this year. I think it's rust. It starts with rust colored spots on the underside of the leaves, then yellow discoloring shows up on the top side of the leaves. Doesn't appear to be killing plants, but sure is unsightly. We had a very wet spring, and that's when this started.

I've cut affected plants back severely, and am picking off affected leaves. Also washing hands between plants. But that's getting putsy, and this keeps coming back. I read on another forum about using corn meal/flour to control fungus, so I am trying this. I just bought a bag of corn flour and liberally sprinkled it on the plants. I'm going to go out and shake the excess off, then water. (Our wet weather has ended, now we are actually quite dry.)

Has anyone else tried this? I'm trying to get my pellies ready to take cuttings for overwintering plants, and I'm hoping to not bring any of this fungus into my sunroom for the winter.

Also, does anyone have any idea if this fungus would be harmful to pet rabbits? I know this is a bit off topic for a gardening forum, but our three bunnies are partners in the pelargonium growing operation. They provide fertilizer in exchange for pelargonium leaves. Three or four pelargonium leaves is the bunnies daily treat all winter long. (The bunnies and pelargoniums live in the same sunroom all winter. It's a little slice of heaven in there when the snow is piling up outside. Cute bunnies, pretty flowers. Life is good!)

Follow-Up Postings:

RE: Rust on Pelargoniums- Anyone have results with corn meal?

I've never heard that geraniums are prone to rust. They are generally regarded as disease resistant.
I don't think its rust anyway....I think its all in the water....and too much of it. The plants have been sitting in volumes of rain and evidently for quite some time.

Geraniums are one plant that can take and use a lot of water...but even they have a drowning point.
I think the "rust" as you call it is nothing more than a fungus that probably occurred because the plants were wet a long time. Full sun should have brought them back.

I would just clean up the plant as the brown leaves occur and water the watering now that the rains have stopped.
Hopefully too, the plants...where you have drain very well. That is a must.

If you continue to experience browning leaves, I would suggest you NOT use them for cuttings. Cuttings should always be from healthy plants...otherwise you are just compounding the problem.

Too, if these, just by chance, are Martha Washingtons, these particular pelargoniums do not produce cuttings that hold up well.

RE: Rust on Pelargoniums- Anyone have results with corn meal?

Actually, geraniums/pelargoniums are very prone to rust and it sounds like you've got it. :(

I've never heard of trying cornmeal and I don't know if it would be harmful to rabbits, but you should take away all affected leaves and quarantine the affected plants until you can get rid of it.

Hope that helps!

RE: Rust on Pelargoniums- Anyone have results with corn meal?

Thanks. I'm going to research this fungus to see what else I can learn about it. The pelargoniums I have are just a non-patented bicolor zonal bedding pellie from the loacal chain garden center. I need to have some healthy stock to overwinter, as I need 90 of these beauties to bring to next year's county fair. The rust is very discouraging.

I'm cutting the plants that have it all the way back to almost soil level, applying corn meal to the top of the soil, and hoping. So far, one has some new leaves between a quarter and a half an inch. So far so good.

I do need to quarantine a bit better. My pellies are in recycled (washed with 10% bleach solution,) one gallon pots, which sit in whiskey barrels. I've got the pellies spaced out so they don't touch each other, but there are two or three in each barrel. Also, we have three cherry trees in the front yard which have a spotty fungus terribly (probably rust as well.) Those trees my DH wanted to maintain, but he's lost interest, so I should work on those too, or it will just be back over on my pellies. Wisconsin is so darn fungussy, moldy, mildewy!!

I'm just frustrated. This is just a garden challenge I have to learn to overcome. I'm going to beef up my sanitation methods. Maybe it's time to be ruthless and throw out all affected plants. It's so hard to do. Some of these plants I've had for three years :-(

Thanks for listening.

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