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Hollyhock rust


by Pippa Greenwood

I'm sure I'm tempting fate here, so this is a whispered blog... but my hollyhocks don't have rust.


Hollyhock rust on hollyhock (Alcea rosea) leafI'm sure I'm tempting fate here, so this is a somewhat whispered blog... but my hollyhocks don't have rust.

I planted my hollyhocks about eight or ten years ago; some are now nearly as tall as me, but most of them are just half my height. As yet, their foliage is perfect; there's no hint of the telltale raised orange-brown pustules on the undersides of the leaves.

Hollyhock rust is caused by the insidious fungus Puccinia malvacearum and only affects hollyhocks and mallows. The fungus overwinters on infected plant debris, then the spores are carried on air currents to hollyhock or mallow leaves. The leaves are soon infected with rust, becoming distorted and discoloured, then dying back. If the plant suffers from prolonged attacks for several years in a row, it rarely flowers well.

The infection is said to have caused the hollyhock's declining popularity with florists. I can't help wondering, though, if the fact that few of us now have vases or hallways big enough for hollyhocks is also a factor.

We've had a damp start to the year; moisture on leaf surfaces can accelerate infection, so I'm surprised my plants haven't been affected. Last year they weren't so lucky, although the infection wasn't too severe. Now, I've got my fingers, toes and knees crossed, hoping that they remain untouched.

I'll be watching my hollyhocks closely to see if the rust fungus develops. If and when it does, I'll remove infected leaves as soon as I spot the infection, hopefully keeping it under control - but that might not be easy with all my digits and limbs crossed!



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Gardeners' World Web User 05/07/2008 at 09:38

My first year also growing a hollyhock, again planted last year and did nothing, and I have had rust and scrapped the plant. May try again next year as I think they look so lovely.

Gardeners' World Web User 06/07/2008 at 12:53

I planted hollyhocks last year, nothing happened! However, this year 1 is more than 6' tall with lovely red flowers, (just opening) the shoot off it will be opening soon. HOWEVER, I didn't realise there was such a thing as hollyhock rust and boy! do I have some! You suggest removing leaves, is this all I can do, or should I spray with something - eg Fairy Liquid? Please give me some hints please. I also have a Mallow, but quite a few yards away. Will this one be OK?

Gardeners' World Web User 06/07/2008 at 15:37

Please can you tell me can i grow Helleborus from seed. Love the programme. thank you.

Gardeners' World Web User 07/07/2008 at 13:07

My hollyhocks have suffered so much with rust all I had left last year were a spikes of flowers with no leaves, so this year I've started again from scratch from seed. I have 8 heathy little plants in 3" pots in the greenhouse, I did notice yesterday 3 more had come through in the seed tray I used which I had put outside the greenhouse. Do they germinate at different times for any reason and do you think its worth hanging on to the tray a while longer? in case any more will come.I've never grown them from seed before I've always bought plants ready for flowering that year, so how long do I leave them in their own pots before planting them into the garden? and now they're between 2-3" across do I leave them in the greenhouse or not?

Gardeners' World Web User 07/07/2008 at 13:08

My hollyhocks have suffered so much with rust all I had left last year were a spikes of flowers with no leaves, so this year I've started again from scratch from seed. I have 8 healthy little plants in 3" pots in the greenhouse, I did notice yesterday 3 more had come through in the seed tray I used which I had put outside the greenhouse. Do they germinate at different times for any reason and do you think its worth hanging on to the tray a while longer? in case any more will come.I've never grown them from seed before I've always bought plants ready for flowering that year, so how long do I leave them in their own pots before planting them into the garden? and now they're between 2-3" across do I leave them in the greenhouse or not?

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