How Cold can Helleborus take?

[Paul T]

Howdy All,

This isn't a cultivation problem, but rather a cultivation question...... How cold will Helleborus survive to?  I have been talking with someone in a much colder climate than myself (way up high in the northern hemisphere) and they do not know whether there will be any point growing Helleborus as they don't know whether they'd survive or not?  I'm in such a comparatively mild climate that I really can't comment on it, but I figured that there would be others here who would be likely to know.

Any ideas?  I realise that some species will likely take colder than others, but for a start how cold do the basic "orientalis hybrids" that we grow in our gardens take?  And H. corsicus?  What about the other species?

[Roberto Gamoletti]

Paul,
I live in north Italy and I am growing hellebores outside in the garden. They have never suffered damages from winter frost. I remember hellebores in pots in which the soil was completely frozen but the plants survived without problems.
This is true both for orientalis hybrids and most species with exception of h.lividus and h.vesicarius in my experience.

Roberto

[Joakim B]

Paul since some of the helleborus lives in Central Europe (Hungary and Ex Yugoslavia) they get cold winters like -20C or so. We have had winters of -10-15C in Sweden. Not sure if it is valid for all kinds.
Kind regards
Joakim

[Staale]

Paul
A lot of Helleborus species grow well in many gardens in Norway. I have foetidus, torquatus, niger and purpurascens all triving and growing, together with several hybrids. They have taken -25 C with very little snow cover. From time to time I do loose a couple of plants in winter, so I guess I might be stretching their limits here.

[Paul T]

Thanks for the responses everyone.  I shall try sending some seed of my double orientalis hybrids to my friend and see how they go for them.  Worth a try from seed at least, although I imagine if I sent an actual plant it would probably die of shock! 

[johnw]

Paul - Here in coastal Nova Scotia argutifolius must be planted near the house or a wall in a spot with good drainage and protected from excess wind and winter sun. Otherwise it will die or the tops will freeze to the ground.

H. foetidus need good drainage and appreciates winter shade as well but is quite a bit hardier than argutifolius. Can get scorched in an extremely bad winter with no snow cover.

H. lividus is definitely very tender but has survived a few mild winters, those that have performed long term are mis-labelled and most likely lividus x arg.

H. vesicarius - not a plant for here.

H. x nigercors is ok but needs a site similar to argutifolius.

The rest are as tough as old boots.

johnw

[Paul T]

Thanks John.  Good solid info, which hopefully will be useful to anyone else reading this as well.  Interesting to know that everything else is fine for you.  Out of interest, how cold do you get in winter?  I am sometimes glad that I live in this nice "middle" climate that allows me to grow so many cold climate things while still growing warm climate stuff in sheltered areas.

[johnw]

Paul - The record low is -25c in 1993 with tons of snow on the ground.  usually we go to at least -15c/-17 every winter. The last week of January and the first week of February are the coldest when the effect of the ocean fizzles. We will have a few days with highs of -12 to -14c with or without snow. Worst of all are those days of late March when the ground is frozen, the temp at or below freezing and latitude 45 degrees sun blazing away - we have more damage then than from winter lows it seems. We get about 100mm or more of rain (or snow) every month (60 odd inches a year). Autumns are mild and then a sudden plunge in early December (to about -12c) sometimes without an intervening frost- doesn't help hardening off much. I believe November is the wettest month.

johnw
 
 

[Paul T]

John,

Sounds cold just reading about it!!  And I'm in the middle of winter here already!!