Scottish Rock Garden Club Forum
Seedy Subjects! => Grow From Seed => Topic started by: Robert G on November 30, 2009, 07:24:09 PM
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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?
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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.
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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.
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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.
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Robert, I like your pioneering plant spirit! Good luck!!
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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. 8)
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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 ... :)
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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
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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.
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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.....
[attach=1]
.... sometimes they can be frozen for a couple of weeks at a time... .plant defrosted
[attach=2]
and a few weeks later.... with flowers....
[attach=3]
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Maggi,
Thank you for the great pictures, even if they do make me a little bit jealous. Something to look forward to.
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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. :)
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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.
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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.
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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.
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Different ssp of Arum italicum grow here (zone3) outside provided they are protected (mulched) and covered with snow. Seedlings can sometimes be hardier than adult bulbs.
As for the aroid hardiness list I would be rather careful. Min. temperature can be indicated for a short period of time (not for a 5-6 month winter we have) or for dry conditions etc. I've lost some arisaemas as I believed the list and left them outside for winter. Winters differ.
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Oleg's qualification is definitely true. You have to experiment with your own areas. The hardiness list is just examples or where things have survived. It can often give you a hint that something might survive that otherwise would not have. So much of course comes down to the genetic material you have as well.... some strains of a plant have adapted to warmer areas while other strains have adapted to colder areas. Growing from seed helps, but it can sometimes depend where that seed came from in the first place as to how much cold/warm it will take.
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Oleg, I suspect you and I gave similiar conditions. Here we can have -30c for a week without snow cover, a week of rain, or -5c with a lot of snow. Last year was normal, but we increasingly seem to have unstable winters. Always some cold -30c.
Paul and Oleg, you are both right about the list. Winter wet and snowless extreme cold, etc.... Too many factors.
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What we also should not forget is that the world's climate has never been 'stable' and some of these plants have been around a long long time. Some plants, from areas which are warm now, may have experienced weather patterns we wouldn't deem 'normal' for those areas now. You just have to give them a try. ;)
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And remember, the plants themselves don't read the books so they don't necessarily "know" that they're supposed to not grow in your climate. A lot of my plants survive because I have heartlessly kept them illiterate, so they don't know that they aren't supposed to grow in my climate (my Beaugainvillea which is in full flower at present, as an example). I never let me plants near my reference books, just in case they find out that they shouldn't be growing here in Canberra. ;D ;D ;)
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Good point too, Paul. Another thing to keep plants away from are references to their distribution in the wild- or they may realise they aren't suppose to be found in the wild in a particular location. I think this is perticularly important for all those plants that are found within metres of the Bulgarian borders with Romania, Serbia, Macedonia, Greece and/ or Turkey- but not actually in Bulgaria. ;)