Holly Hock Rust

k.zalewskyJune 16, 2006

I am very new to this forum and was wondering what I can do besides clipping off the affected leaves to stop holly hock rust?

I've read about certain fungicides in early spring, but want to use organic.

Any tips would be great. It is mutilating my 3 holly hock plants.

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dchall_san_antonio(8 San Antonio)

Fill your adjustable hose end sprayer with milk, set the dilution to 3 ounces per gallon, and hose it down. Do that every other week. I would not expect immediate results (typical for organic solutions), but I would expect results. Give it 21 full days to cure it.

    Bookmark   June 16, 2006 at 9:27PM
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OK, I hate Hollyhock rust with a passion. Just one of those things. Beautiful plant and flowers when grown without the rust, but when rust takes over and even affects the buds, it's either time to call it quits or take action. Especially when it starts to affect every member of the Alcea family and you are trying to grow the Marshmallow plant (Althaea Officinalis).

If it's not too bad yet, start amending the soil with good compost and then top it off with corn meal. By 'not bad yet' I mean that some leaves and the stem are not showing any rust at all. That should start curbing the rust. (Notice I use the word 'should'...)

In my case, I removed all plants and threw out all but the Marshmallow plants. (Make sure you dispose of them in the garbage and not in the compost. Burn them if you can!) In the areas I removed plants, I amended the soil heavily with compost and corn meal in September and let it sit throughout the winter with a nice mulch of shredded leaves on top. In the spring I replanted with small plants which I'd started in another garden and showed no signs of rust. Out of 6 plants, only two showed signs of rust on occasion, but it was minimal and I removed the leaves and continued to apply the corn meal at the base. It solved the problem.

For the Marshmallow plants, since their tap roots were huge, I cut them back to 3 inches from the ground, then dug out the surrounding soil and replaced with soil amended with compost and corn meal. Worked like a charm. Saw a bit of rust last year, but so far this year there's nothing.
Again, make sure you dispose of any plant material properly so you don't end up with a worse problem. And if you touch an affected plant, wash your hands before touching the healthy ones.

That's how I handled the problem and now I have wonderful HHs growing in the gardens again. Also, try to choose the fig leaf variety or singles since they are less susceptible to rust. Their simplicity is also gorgeous!

Apparently you can also use sulfur dust on the problem, but I prefer to get at the root of the problem and nip it in the bud vs choking things to death. (Pardon the puns, eh?!)

    Bookmark   June 16, 2006 at 9:29PM
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Could you not have written in a few minutes earlier so that I would not have to write an essay on how I solved my problem the hard way??? LOL!! :)

    Bookmark   June 16, 2006 at 9:32PM
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Hollyhocks growing in soils too rich get rust much easier than hollyhocks growing in soils that are leaner and meaner. There are hollyhocks growing wild in some open soil between a parking lot and an alley that get no attention from anyone, including water. These grow profusely with lots of flowers and no rust even though within 3 blocks someone has some, maybe seeded from these, that have rust every year. Much better soil?
The self seeded hollyhocks in one planting bed at the church grow abudantly with no rust but around the corner some self seeded hollyhocks, richer soil, get that rust.
Just my observations.

    Bookmark   June 17, 2006 at 7:49AM
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paulns(NS zone 6a)

Hollyhocks we gave the corn meal treatment to last year have no rust this year; the others do. I plan to repeat this experiment.

On the other hand Kimm I think there's something in what you say. People here tell me their grandmothers always had hollyhocks growing beside the house, never fertilized and never heard of rust. I planted hollyhocks in soil amended with compost and fertilized yearly and the rust is terrible. The same people ask me for hollyhock seed or plants and I hesitate to give them any for fear they will get rusty.

    Bookmark   June 17, 2006 at 12:46PM
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how do you make a soil less rich if you hae rich soil where your hh grows?

    Bookmark   June 17, 2006 at 2:03PM
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byron(4a/5b NH)



I have one, old fashioned single blossom that is a tad over 30 years old. It gets a shovel full of 20+ year old horsemanure every year.. No rust


    Bookmark   June 17, 2006 at 7:39PM
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The type of soil doesn't really matter. I do have some growing in not so good soil. Quite well, I might add.

The problem is when the fungus is present on (in?) the soil, or if you've purchased one with the spores or if growing from seed, have used seeds infected with spores.

    Bookmark   June 17, 2006 at 8:17PM
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why not 1:1 ratio of water:milk?

    Bookmark   June 17, 2006 at 11:18PM
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thank you for all your information. It is pretty bad on all 3 plants and I may try the milk solution and cornmeal in the late summer too. I really don't want to have to pull them out just yet. I've been disposing of the dead leaves and ones I've cut off int he garbage and not composting so as not to spread it to others in the family.

Thanx again

    Bookmark   June 18, 2006 at 2:41PM
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As I began posting three years ago, cornmeal will control hollyhock rust. Now that it is present in your soil you must begin treatment early every spring. The minute that you see signs of the first sprouts, dust the area with cornmeal and repeat every two weeks throughout the growing season. I was not aware that milk also controlled hollyhock rust. Would like to hear more from those who have tried the milk treatment.

    Bookmark   June 18, 2006 at 3:26PM
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rosebush(z7 NC)

That would explain why my HHs have had no rust this year. The first year I planted them I amended the soil like crazy. When they finally bloomed, they got rust. This year I haven't had time to amend the soil as my veggie beds have grown larger and needed more care. No rust! Now it must be noted too that we've had a much drier season and I've also been careful of cleaning up the dead leaves and blooms. But I have seen various plants grow stronger when they have to work at it a bit. Kind of like people. . .

    Bookmark   June 18, 2006 at 9:44PM
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dchall_san_antonio(8 San Antonio)

If Nandina says corn meal will work, then it will work. I don't grow hollyhocks, but when I see 'rust,' I just assume that corn meal will be ineffective (as it is in the turf disease of the same name). Compost and corn meal should be on the surface of every garden soil IMHO.

    Bookmark   June 18, 2006 at 11:46PM
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Hollyhock rust does not exist in soil, it completes it life cycle on plant parts only. It may overwinter in the spore stage on plant debris left on top of the soil, but this rust is not "present in soil" as such. This rust is spread primarily from wind blown spores. The link explains it well. Along with proper watering and sanitation, wettable sulfur is an effective fungicide for this disease if applied at the right times.

Here is a link that might be useful: CSU

    Bookmark   June 19, 2006 at 1:09AM
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paulns(NS zone 6a)

Another suggestion I read in a gardening book is to accept the rust and grow a different, lower, later perennial in front of the hollyhocks to hide the wreckage.

    Bookmark   June 19, 2006 at 8:37AM
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lblack61(z5 NY)

Wow, I'm learning a lot from this post. I have Hollyhocks this year and watched as my plant went from a bushy, full, healthy plant at the back of the border to almost leafless (because I had to pluck them all off).

I read something about the weed Mallow being a spreader of the fungus...and I have have a lot of that (I now notice)in the spot I'm growing the HHs. The weed has some serious roots (it is impossible for me to dig it up and get it all because I would probably have to get a front-loader and dig up a trench in my yard).
Does cornmeal work as an end-of-the-season treatment too (i.e. amending the soil with it in the fall after cleaning up the bed)?

    Bookmark   July 5, 2006 at 7:48AM
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prairiemoon2 z6 MA

Thanks all...I have been very disappointed to find a bad case of rust on HHs that were winter sown in 2004 and just coming into bloom now. The foliage was looking fine, so not sure when it started showing signs of rust, as I have been distracted by other areas of the yard needing attention. One plant nearest the downspout against the house, is just covered. I think I would like to just pull them all out of there, but then it is going to leave a very large hole in a border, that I have no idea what I could add this late in the season that wouldn't take all summer to fill in.

BTW, would there be any problem growing delphinium in the same place you had a HH that had rust on it?

One more question...if the rust can contaminate the seed, then where can you possibly find seed that is not contaminated, if most people have it?


    Bookmark   July 5, 2006 at 9:33AM
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rouge plants around your downspout and design a system to manage water run-off:either a "french drain"or rainwater collecting barrels for reuse...
In my view,shifting patterns of precipitation,heat,drought, prolonged waterlogged soils and so forth are some of the issues that will influence how we view wintering over of pathogens, what we grow and where we obtain seeds....Mother Nature is testing our "cleverness"...

    Bookmark   July 5, 2006 at 12:17PM
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byron(4a/5b NH)

Move to Mid west where it is not as wet as Northeast :-)

    Bookmark   July 5, 2006 at 9:08PM
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Now Byron, be nice. We like our Northeast places... well, maybe this year with all the rain we might consider moving... but then again, maybe not. :)


I get HH seeds from plants which I see have no rust which friends or others grow. In terms of commercial seeds, I won't plant the new HH in the gardens for a year, hoping that it will show whether or not it has rust during that time - which they usually do.

Planting Delphs in your old HH area won't be a problem.

    Bookmark   July 5, 2006 at 9:57PM
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prairiemoon2 z6 MA


Thanks very much for answering my two questions. :-)
So when it is time to trade seeds, do you trade your Hollyhock seeds? I don't have any friends with Hollyhocks, rusty or not. [g]

Still not moving from the Northeast either. :-)

    Bookmark   July 11, 2006 at 2:03PM
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I'm reviving this old thread because my HH has rust and I didn't know what caused it or how to treat it. I'm still confused a bit on the exact cause, as it sounds like some think over watering contributes, plus the fungus and apparently too rich of soil.

I just removed all the effected leaves, did the cornmeal thing, and wonder now if all of my seedlings in pots nearby should be moved to another area of my yard to keep them away from the one with rust?

This was a gorgeous hollyhock before the rust, and I looked up this topic hoping to glean information. I found a lot, but would still appreciate these answers.


    Bookmark   July 6, 2009 at 11:04AM
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I have been battling with hollyhock rust lately and it makes me wonder... years ago I took on a garden project where you couldn't stop the hollyhocks from growing in a crushed stone walkway lined with landscaping fabric, I would dig them out as fast as i could an they would always come back!!! Not that I didn't love them, but they were literally in the middle of a walkway, anyway, they were always beautiful with no signs of rust, no place for the spores to harbor maybe???

    Bookmark   July 15, 2012 at 9:47PM
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I am new to the forum and would like to thank all of you with so much knowledge. I have frequented this site dozens of times when trying to find an organic solution to my plant problems or just needed a question answered. I am new to outdoor gardening, I enjoy it greatly. When my Holly Hocks started showing yellow clusters on the bottom leaves, I assumed I had an insect problem, so I came straight to this forum to check. Nope, not insects. Who would have thought corn meal would be a solution. I will remember to put the corn meal in my bed next year. They were doing just fine until we had rain, rain and more rain. I do believe we have set a record with rain fall this year and it has not been good for any of my flowers other than huge bed of Lilly, they seem to like it. Thank you everyone for all the help. I would like to post a photo soon of some beautiful flowers I planted from seed, I planted so many seeds I do not remember what they are, but I adore them and want to plant a lot more of them next year, perhaps someone can identify them for me.

    Bookmark   July 28, 2013 at 5:44PM
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OK how much cornmeal is required for one plant ??????

    Bookmark   July 6, 2014 at 9:30PM
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