I think it may depend on the species - the wholesale grower I used to work for marketed cultivars of Erodium x variabile as a groundcover hardy to zone 5/6. We sold a lot of it to the eastern half of the state, a big chunk of which is zone 6 or colder and it seemed to be fine. E. corsicum is one of the parents of this naturally occurring hybrid and is arguably the hardiest of the genus, rated to zone 4. E. chelianthifolium is rated to zone 5. Most others are listed only to zone 7, some even higher.

Glad this question came up! I have kept away from Erodium for the same reason, thinking they might not be terribly hardy here. But lately I have been thinking of trying one. Thanks for the info gardengal, now I know what ones should do well here.

"When in doubt, plant a Geranium" Ah! That's a motto I live by! ;-)
CMK

Erodium chrysanthum is very hardy. It has pretty, ferny grey leaves, grows about 6" tall & 24" wide, and likes full sun & good drainage. The flowers are smallish & cream colored - pleasant, but not outstanding. I've grown mine in a rock garden for about 10 years. Unfortunately, none of the showier species or hybrids I've tried have been hardy for me.
Jays

I've grown erodium manescavii for many years and find it hardy here, very easy and trouble free. It's only problem, if one wants to label it such, is that it seeds around quite a bit. It's extremely long blooming as well.

I'm in zone4, I had 4 different types of Erodiums survive last winter.
Some manescavi ( one rotted but still came back later), E. Lindavicum, E.Carvifolium and E. Cedrorum.
No mulching but we did have 4 feet of snow cover for months.
I have some E. Gruinum volunteers in the garden at the moment but don't expect them to survive.
I also have an E. Trifolium seedling that I have left outside for winter. I dug one up and brought in just in case.

Maggiepie, I know E. manescavii, which is a larger type, but are the others all small rock garden varieties?

E. carvifolium and E. trifolium (syn. E. hymenodes) are both about 30cm (12") in height and typically described as for "front of the border" use.

Ontnative, I can only find pics of flowers mostly.
E Carvifolium is less than half the size of Manescavi but the flowers are pretty much the same color.
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E Cedrorum is only a few inches high but spreads out and weaves its way between other plants but doesn't put down new roots.
It flowers almost non stop until hard frost.

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Erodium Lindavicum gets to about 5 inches high in my garden.

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Erodium Gruinum gets to 30 cms or so. The flowers are a beautiful blue.

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Erodium Trifolium is around 20cms at the moment.( It was supposed to be E Pelargonifolium)

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Maggiepie/Coolplantsguy: Thanks so much for the info and pics of erodiums. I will have to try some of the varieties you described. We usually get good snow cover here (south. Ontario) so I am thinking they should do OK. E. manescavii certainly did, before I ripped it out due to overgenerous self-seeding.

Ontnative, so far I have yet to see even one self seeded E. Manescavi seedling, only ones that have self seeded for me are the E. Gruinums.

Do you grow many hardy geraniums? If so, do you have a list?

coolplantsguy, do you have a list of Erodiums and hardy geraniums that you grow?

-maggiepie, wonderful pics! I have to see if I can find those kinds next year, yours are amazing.
CMK

Maggiepie, I've never grown an Erodium in my garden (hence my original question), but your pics are certainly inspiring, especially E. carvifolium and E. gruinum.

As for Geraniums, here's what I've grown in my garden(s) over the years:

'Ann Folkard'
'Blue Sunrise'
'Brookside'
cantabrigiense 'Cambridge'
cinereum 'Ballerina'
clarkei 'Kashmir White'
himalayense 'Gravetye'
'Johnson's Blue'
'Jolly Bee'
macrorrhizum (several forms)
maculatum 'Beth Chatto'
maculatum 'Elizabeth Ann'
Ãmagnificum
'Patricia'
phaeum 'Samobor'
'Philippe Vapelle'
pratense 'Mrs. Kendall Clark'
psilostemon
renardii
'Rozanne'
sanguineum (several forms)
'Spinners'

Planted this spring/summer:

'Dragon Heart'
'Perfect Storm'
'Sandrine'

-coolplantsguy, I have been thinking about getting 'Blue Sunrise'. What is your opinion of it? Is the golden foliage brighter in full sun? How long does the golden color last before greening out?
CMK

I like it in general. For some reason I prefer its flower/foliage combination over some of the others that have so-called golden foliage.

In a previous with several hours of direct sun it did well, flowering for a long time, and holding its golden foliage well into the summer, turning more of a true chartreuse instead of green. In my current garden, it's in more shade, where it seems to lack vigour.

Thanks for the info!
CMK

Thanks christinmk, good luck with your plants.

coolplantsguy, I will keep my eye out for Blue Sunrise, that is a new one to me and looks lovely.
Not easy to find them here.
I did get Perfect Storm this year and am very pleased with it apart from the way it looks when the flowers age.
I also bought Elke which is quite lovely, hope it survives winter.
This year my Ãmagnificum developed rust, am thinking of pitching it.

Maggiepie, I like to "collect" hardy geraniums, so have fun growing many different cultivars. I have most of the ones that coolplantsguy has (except his NEW ones) plus the following:

cantabrigiense 'Biokovo'
cantabrigiense 'Karmina'
cantabrigiense 'St. Ola'
cantabrigiense 'Westray'
oxonianum 'Claridge Druce'
oxonianum 'Thurstonianum'
'Sue Crug'
riverleaianum 'Mavis Simpson'
cinereum 'Lawrence Flatman'
cinereum 'Alice'
'Kashmir Blue'
clarkei 'Kashmir Purple'
'Terre Franche'
'Tiny Monster'
'Dilys'
'Nimbus'
sang. var. striatum
sang. 'John Elsley'
sang. 'Alpenglow'
sang. 'Ankum's Pride'
sang. 'Canon Miles'
sang. 'Max Frei'
sang. 'New Hampshire Purple'
sang. 'Elke'
maculatum (native)
maculatum 'Espresso'
phaeum album
phaeum variegatum ?
phaeum 'Springtime'
asphodeloides
magnificum 'Rosemoor'
pratense 'New Dimension'
pratense striatum aka 'Splish Splash'
macrorrhizum 'Bevan's'
macrorrhizum 'Ingwersen's Var.'
macrorrhizum 'Spessart'
macrorrhizum variegatum
'Tanya Rendall'
'Salome'
subcaulescens
wallichianum 'Buxton's Var.'
sylvaticum 'Amy Doncaster'
sylvaticum 'Mayflower'
sylvaticum album
wlassovianum
yoshinoi 'Confetti'
nodosum
pyrenaicum f. albiflorum
dalmaticum

I'm always on the lookout at garden centres and plant sales for new, worthwhile varieties that I don't have. Just because it's a new variety doesn't mean it's better or different than what I'm already growing. Many of the oxonianums, sanguineums and phaeums look very similar to each other, so it is pointless trying to grow too many almost identical cultivars.
Did you grow your erodiums from seed or purchased plants?
I have included a link to a geranium nursery in the UK which has good pictures.

Here is a link that might be useful: geranium nursery

ontnative, you have a terrific collection of geraniums.
Like you, I am always on the lookout for new plants but this year there were hardly any old or new geraniums available.
Perfect Storm, Elke and Phaeum Calligrapher were the only ones I bought.
All the erodiums I posted were grown from seed.
I do have a Bishop's Form and a white version of it inside, those were sent to me by a friend in Calgary.

They seem to have a much better selection there than here in New Brunswick.
I'm sure you have lots more choice in Ontario too.