Where to over winter my sub tropical bonsai in uk?

[Kipper10]

Hi, I am in uk and have a few sub tropical trees. I have 2 options to over winter them.
I have a north east facing conservatory that gets sun in morning only. It does have a radiator in there that is on in the daytime but it does still get cold is it is not sufficient to heat it properly. But we do use the conservatory for 2 weeks at Christmas when it will be heated in the daytime to 22C.
The other option is to keep them in the house which will be heated to 22C during the daytime and can be on a south or east facing window.
Can anyone advise which is the best option please?

 

[oranjeaap]

You should first tell us the species.
Being in the UK you will most likely need to give them every minute of direct sunlight you can, so South facing would always be preferred. But winter temperature requirements can vary wildly between (sub)tropical species. So some species might prefer the cold conservatory over the South facing window.

 

[Kipper10]

Thank you for your reply. The ones that I will bring inside are Serissa, Pomegranate, Chinese Pepper and Chinese elm.

 

[Shibui]

Pomegranate and Serrissa can both cope with temperatures down to freezing. They'll always look better with temps a little higher but certainly don't require you to keep them over 10C. Pomegranate is deciduous here so won't need sun if/when it drops leaves.
Chinese elm has no problems down to -3C here. Mine all live outside all year round. Chinese elm is deciduous when temps get below around 5C so should not need light through winter if you let it get cool enough to drop leaves.
Don't know about Chinese pepper?

Heated hoses can cause a host of problems with plants - low humidity, low air movement, low light levels, etc. I cannot compare your south window option with the conservatory option but I suspect the conservatory might be a better option for plants that don't require higher temps.

 

[Kipper10]

Thank you for your reply I think I will keep them in the conservatory, I’m not brave enough to keep them outside, will worry about them
The Chinese pepper is called Xanthoxylum Piperitum they are sold as indoor bonsai.

 

[Shibui]

The Chinese pepper is called Xanthoxylum Piperitum they are sold as indoor bonsai.

I already searched the common name and found the proper name but have never heard of that species down here so still can't help with any clues on cold hardiness or not for that one.
Good luck with your winter but the 3 I grow are quite cold tolerant so any problems are not likely to be cold related. Probably better to focus on soil moisture instead. Too wet for too long or too dry can be killers, even in winter.

 

[leatherback]

, I’m not brave enough to keep them outside, will worry about them

I would be more worried about keeping cold-hardy plants inside for winter to be honest. Plants from non-tropical regiong NEED a period of colder weather to remain healthy.

UK is a big place, with climates from near-mediteranean to full on cold. Where you are matters a lot in what you can do.
Xanthoxylum Piperitum is hardy down to -15C afaik.

 

[Kipper10]

Thank you for your replies. We don’t seem to get cold winters here very much anymore, we are right in centre of uk near Birmingham and I do have a cold frame and a sheltered garden I think I’ll be a bit braver and keep them out unless the weather is extreme then maybe put them in the shed or garage.

 

[WNC Bonsai]

Thank you for your replies. We don’t seem to get cold winters here very much anymore, we are right in centre of uk near Birmingham and I do have a cold frame and a sheltered garden I think I’ll be a bit braver and keep them out unless the weather is extreme then maybe put them in the shed or garage.

I like to froze to death in Birmingham in November 2023, so don’t tell me it doesn’t get cold there! And if the AMOC collapses you’ll be a lot colder. At any rate get them settled in for winter and don’t move them around unless you see a real arctic outbreak coming then shift to the shed or garage. My problem was the all too frequent polar vortex air masses dropping our temps into the 10-20 degrees F followed quickly by a warm spell in the 60-70 degree range and then back to freezing again. A few of those kinds of freeze thaw freeze cycles can really stress trees and my back. The main thing is to insulate them against killing temps as well as the freeze thaw cycles and rapid temp swings.

 

[leatherback]

Thank you for your replies. We don’t seem to get cold winters here very much anymore, we are right in centre of uk near Birmingham and I do have a cold frame and a sheltered garden I think I’ll be a bit braver and keep them out unless the weather is extreme then maybe put them in the shed or garage.

Best would be to check cold hardiness for each plant. Stay on the safe side, as plnats in pots are slightly more sensitive than those in the full ground.

The USDA hardiness measure is a good tool to use, as there are loads of global maps with the USDA hardiness zones.