Hello,

a couple of my trees have come out of their winter sleep a bit early and it is supposed to get down to -7 C in the next couple of weeks.

I have read a number of differening ideas about what to do. I know I should try and keep the pot from freezing, but how do I protect the foliage? I do have shelves to build a makeshift greenhouse, but the -7 nighttime temps should only last a couple of days. Would covering the foliage be enough? I do have the trees on a balcony which tends to stay warmer than the outside air. But at that temperature it probably will get a bit colder than 0.
any thoughts, ideas?

An idea would be to put them as close together as possible by a glass door with heat on the other side and put a tarp or something windproof around a framework of some kind. That will bleed a lot of heat and should help.

The joys of late frost..
Curious .. where are you that you have leaves already?

I am not sure whether the greenhous can easily be replaced. If you do not have many trees, you could of course bring them in an unheated space. Car, garage, bedroom etc for the one or two nights?

I live in Germany, not far from Düsseldorf. but in the city. It has been warm and sunny the week or so. My crabapple was early last year. I'm thinking Greenhouse is the way to go. If I brought them inside, should I leave the window open in the unheated room, or just leave the heat off?

Wow.. Just a good 100km from you in Ahaus we have been having frost every night for the last month or so. Expected to stay that way for at least 2 more weeks.

A bit hard to tell what to do as we do not know your local situation.I would leave the thing open during the day when sun can get to it. ANd during the evening/night close up?

I have two balconies. usually, if the temperature doesn't get below -3 or -4 they both stay above freezing. The front one faces west, and the back one faces east. The back one stays above freezing down to -5. on my front one, I've (re)built the makeshift greenhouse with bubblewrap. that should be fine.
The front balcony gets a lot more sun than the back one, which is my reason for concern. I want to give the trees that have started growing more sun.

I am considering getting one of those things that they make for tomatoes for the back one. but just for those time when it gets really cold. As buying bubble wrap every year can get expensive and is wasteful.

does that help?

Just a quick update.. the sub-freezing temps seem to be behind us, and my crabapple an other trees which were growing seem to be doing fine, despite repot, and about a week in a greenhouse.
as you can See the flower budy are starting to come out already.

Today I could have a look at my plants (I am not at home often, only in the weekends).
So far it seems all trees are doing fine (though I can't be sure yet - I'll know once spring really starts).

My Chaenomeles was full of flower buds before this cold period started. I know these buds fall off very easily. However, they are still there and they are not damaged. It has more buds than ever before... the flowers will be bright red. I am looking forward to that.

(this is a mallsai that I purchased some time ago, hoping to turn it into a bonsai. So far that's not really working out yet. The flowers will be nice though )

For a mallsai, it doesn't look that bad. I'm going to make a separate post for my crabapple when it opens up a bit more.

Just got home after travelling 3 months. The frost has taken some of my trees