Arum seedlings

[Robert G]

I have never grown Arums before but now have some seedlings just germinating outside. Arum italicum ssp. albispathum to be specific. The question is what is the best approach. I am not comfortable with leaving them outside, but should they be kept cool or is a heated greenhouse fine?

[Maggi Young]

I've seen this given as hardy Zone 6, Robert. From South western Europe so I think you'd be wise to give some protection.

Under cover, then I would say cool but not heated. 

[Lesley Cox]

Without knowing much about the whole genus Arum, I'd be inclined to agree with Maggi, especially for little ones which could easily get too hot and perhaps humid in a heated glasshouse. They could rot off. So protected but without heat.

[Robert G]

Maggi and Lesley,

Thanks for your replies. You confirmed what I was thinking. I figured if the natural cold of fall was a germintion trigger  then it would not want heat to continue growing. Maggi I have seen the zone 6 ratings and a few optimistic zone 5s...I am an optimistic zone 4. You can't blame a guy for trying. Some will be enjoyed in pots and a couple will be test subjects/victims in the great outdoors. Plant deep, mulch and say a little prayer.

[Maggi Young]

Robert, I like your pioneering plant spirit! Good luck!!

[Paul T]

The International Aroid Society hardiness listing shows Arum italicum as hardiness of Zone 4b.

The listing is here ===> http://www.aroid.org/horticulture/hardy.php

So the Arum italicum should potentially be hardy in your area, or at least in a slightly protected location outside for you.

The IAS list is a very handy document when trying to work out the potential hardiness of any Araceae.  Some of them can be really surprising, and far hardier than I had realised.

Hopefully this is a help.

[Maggi Young]

That's a surprise, Paul.... thanks for that link.... useful to compare with other plants one might have an inkling about in one's area ...

[Tony Willis]

The leaves usually collapse in a hard frost but recover.Probably the biggest problem will be winter wet,they need a well drained spot.

It may be best to keep them inside the first winter cold but not necessarily frost free and then plant them deep next year outside. In the wild they are usually upto 20cms down and the tubers are probably frost free. Mine have frozen in the greenhouse for many years and no problems but I only get to about -5c

[Robert G]

Paul,
Thank you for the bringing up Aroid hardiness list. I looked at it a while ago regarding Arisaema only and for some reason I didn't clue in about Arums. I had blinders on I guess. That is why I like this forum...the support system. You are right I took another look and it is suprising how hardy some aroids are. More hope for me that I thought

Tony,
Thanks too. I was suprised and worried for the seedlings when I first noticed them they had already experienced -6c. Poor little fellows.  They look good though. Next spring I will make sure they get a well drained sight. I suspect you get a lot more winter rain than we do, but when the snow melts here it overwelms some plants I think. So same problem.

[Maggi Young]

Here are some photos of Arum creticum, in a glass house,  but subject to freezing temperatures.... just as an example of what they can take......

plant with young leaf growth... frozen.....



 .... sometimes they can be frozen for a couple of weeks at a time... .plant defrosted



and a few weeks later.... with flowers....

[Robert G]

Maggi,
Thank you for the great pictures, even if they do make me a little bit jealous. Something to look forward to.

[Maggi Young]

They're photos from Ian's Bulb Log archive, Robert. A. creticum would be less hardy than your babes, I rackon, so I hoped it would cheer you!
I'll try and remember a pip for you next year. 

[Sinchets]

What are your winters like in Metcalfe, Ontario, Robert? We have Arums here native and introduced, which sit quite happily outside under snow with no protection. The leaves don't like the frosts after snowmelt, but as Maggi and Tony say they usually perk back up. We also have recent Arum germinations- more a response perhaps to the plentiful rain in autumn, rather than a desire to be growing through winter snow free.

[Robert G]

Simon,
Winter for me can involve  -30c or slightly worse, but often -10c. We usually have good snow cover. However this year above average temperatures and so far no snow. I am worried that these plants will be damaged by the extreme low temps. I guess I will see. It is interesting that you thought a wet autumn helped to germinate the Arum, that is what we had too.

[Sinchets]

The first winter we gardened here I was worried the cold weather would be the death of pretty much everything. Now as long as we have snow cover I now know that the only problem is predation by 'unseen' voles.
The Arums have all been fine outside and are bulking up. The Biarums looks as if they may soon become weeds. The Arum seedlings came up in October and have been through several weeks of ground frosts followed by warm sunny days with highs of 20C. We don't yet know what kind of winter we will have here' as the snow and cold weather seems late arriving.
The wet autumn also germinated plenty of self sown Cyclamen, Allium, Muscari and Crocus- which I don't normally see until spring- but I don't know if this is because our previous 2 autumns were quite dry. Normally they germinate if sown in pots in the autumn as long as I water enough.