Overwintering mediterranean plants in a non-mediterranean environment

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JTh

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I need help, I have several plants which are commonly used in areas with Mediterranean climate, some of them started from seeds, the plan was to bring them to Greece when the time was right. The problem is that my suitcase is never big enough and I now have several plants here in Norway which have become BIG, and I wonder how to make them survive the winter here. Some have already been transferred from the greenhouse to the basement (it will be too cold for them in the greenhouse), where I have some artificial light, it looks very exotic. The pots with Pandorea jasminoides are there now, but I wonder if I should cut them down now, they are more than three meters tall, or should I wait until next spring? Others are still on my window sill in the living room, but they are hitting the ceiling, at least the Rotheca (s. Clerodendrum) myricoides ‘Ugandense’, which is still in bloom, a Salvia discolor is also quite big, as well as Thunbergia grandiflora. Would it be better for them if I moved these to the basement (the temperature will be about 10 degrees C), or should I keep them in the living room, where the air is very dry in winter.

I know that none the plants I have mentioned here are not of Mediterranean origine, but there was not enough space to specify this in the heading.

Here is one of the pandoreas, on it's way to the basement

_Z110303 Pandorea jasminoides.jpg
by JorunT, on Flickr

and from my window sill, still in bloom

_Z140310 Rotheca myricoides 'Ugandense'.jpg
by Jorun Tharaldsen, on Flickr
« Last Edit: October 01, 2015, 08:37:08 PM by JTh »
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

David Bracey

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #1 on: November 14, 2014, 05:37:55 PM »
Jorun, i would cut them down to root level, pack them with peat and polysterene material, keep them dry and store in a frost free place.
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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JTh

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #2 on: November 15, 2014, 12:18:31 AM »
Thanks, David, that sounds rather drastic though, did you mean that all of them should be treated the same way?

Last winter I kept the Salvia and the Rotheca in the living room, and they did well. I took cuttings of both in the spring, some of them did well and they are now in Greece, where I hope they will survive the winter.
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #3 on: November 16, 2014, 07:49:43 PM »
Jorun
Here in the UK I cut tender salvias back to a couple of inches and tuck them under the staging in a frost free greenhouse or alternatively in the garage. I let them almost dry out and come spring start to water and they soon put on good growth. I am sure it would work for your  plants as David suggests
Helen

David Bracey

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #4 on: November 17, 2014, 07:42:48 AM »
Jorun the key is frost free.
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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JTh

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #5 on: November 17, 2014, 11:18:30 AM »
Thank you, HelenMJ and David. Frost free is not a problem, the main question was if it would be better to keep some of these (especially Salvia discolor and the Rotheca) in my living room at around 21 oC, where there will be more light, or in the basement (10 oC) where there is less light. The Pandorea is already in the basement, and I have to cut it down to make room for it, I suppose it is better to do it now and not to wait until next spring.
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

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Fleur Pavlidis

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #6 on: November 18, 2014, 07:13:05 AM »
When Isabel Sanders was the assistant to Sally at Sparoza she was surprised to see Salvia discolor growing throughout the winter and becoming so big. She told us that at the Edinburgh Botanic Garden (plenty of frost), where she did a course, the plant survived the winter outside but died right down like any perennial and grew back from the roots in the spring. It's much toughter than it looks.
MGS member, Greece. I garden in Attica, Greece and Mt Goulinas (450m) Central Greece

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JTh

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #7 on: November 18, 2014, 04:16:26 PM »
I kept the Salvia discolor in the living room last winter, and it continued growing and lost very few leaves. I wonder if I should do the same this year with this plant, it is maybe less of a stress than cutting it down and keeping it in the cool basement. Then I can cut it down in late winter and try to propagate more plants. I bought it at Sparoza last autumn, originally I had planned to bring it to Greece this spring, but it became too big. The other plants I'll treat as recommended below, soon. It is tough to cut down the Rotheca while it is still in bloom, but I guess I have to do so soon.

Fleur, the Salvia may be tough, but I doubt if it will survive outdoors here. Maybe some years, like last year, but we may as well have days/weeks with - 25 oC or colder, and frost is the  normal from November until mid/end of April.
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

Joanna Savage

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #8 on: November 18, 2014, 07:09:35 PM »
When I was living in a sub-tropical climate I grew Clerodendron ugandense which I think must now be Rotheca. It was a rather shy plant, nothing like the vigour of other Clerodendrons, but with a beautiful pure blue flower. Nothing of the purplish colour in your photo J Th. it was a more subtle and more beautiful plant than Plumbago.  I haven't tried it here in Toscana, but as well as worrying about low temps, I would be thinking about how to keep the rel. humidity high.

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JTh

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #9 on: November 19, 2014, 01:57:46 PM »
You are absolutely right, Joanna, the colour of the Rotheca (Clerodendrum) is absolutely not correct, but that's how it became when shooting indoors in poor light. Blues are notoriously difficult, always, and especially in artificial light. I have again tried to correct it here, and it is not quite as purple, but still not the nice clear blue its should have been. But when I look more closely at the photo, I see several aphids, so I have to do something drastic now.
It is surprising, though, that this plant was for sale here in Norway, I don't think our climate is ideal, too cool in summer, and too dry indoors in winter. In the basement the humidity would be OK for overwintering, I believe.


_Z140316 Rotheca myricoides 'Ugandense'.jpg
by JorunT, on Flickr
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

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Alisdair

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Re: Overwintering mediterranean plants in a non-mediterranean environment
« Reply #10 on: November 19, 2014, 07:41:42 PM »
Jorun, in the spring do let us know how they all fared! (Like you, I'd be tempted to keep the Salvia discolor in your living room in the hope that it'll keep on flowering - it does seem to be prepared to stay in flower almost continuously in the Peloponnese)
Alisdair Aird
Gardens in SE England (Sussex); also coastal Southern Greece, and (in a very small way) South West France; MGS member (and former president); vice chairman RHS Lily Group, past chairman Cyclamen Society