Can we discuss here if we need protection to our trees in certain weather condition?
I can start with my Harglow apricot tree, it suffers form some kind of bark damage and this winter may be crucial for its survival. We expecting several night in a row in negative 5-6 F and days around 10-15. I do have a frame around the tree I can use to cover it. Will it make sense to do it? If yes, do I need a heat source inside the cover?
Is the bark damage on the south west side ?
No, more like on the north - west. I got it from Stark’s with the damage, they send replacement, but replacement died and this one still struggling, 4th year already. I got 3 apricots this summer, they are so good, really want to keep the tree. This year I found another spot where bark not even attached to the cadmium, did some surgery on it. I guess it will either survive the winter or not…
I would not worry about cold damage. I think -5 F should be fine for the fully dormant apricot. We’ll have -10 this night and it should be ok. The cold damages the fruit buds first anyway. You definitely have canker. I would try to plant some rootstock close to the trunk and to make a bridge graft above the damaged area. Or you can saw a bunch of plum seeds near the trunk and to hope that they’ll sprout and grow into the rootstock for the bridge graft.
Agree with Maria that it’s canker. We don’t really have a sun scald issue in our area.
I had similar bad canker on a Satsuma plum. The wound healed well but after a few years I removed the tree because I planted it too close to other trees.
Good idea about graft, I need yo see if I can find some rootstock, though I am not sure a should do this really. I am planting another apricot next spring, harglow as well, but this time from more reputable source, when it start producing, I should be all set, one tree is enough for me, then this one can go. It will be hard to let go the tree I saved once.
If I could find a free rootstock I would try to save the tree just out of curiosity and to make a bridge graft next spring. The bottom canker looks really bad. I do not think that the tree will be able to survive with it without any help. If you are going to plant the new apricot, try to plant it in the place with winter shade, i.e. in the place which is shaded in winter due to the low rising sun. This will delay the flowering and might increase the possibility of fruiting. This is just a thought.
Ha-ha)) My yard is like chess board with 32 square board instead of 64 - every figure has a place, and to move it you have to “eat” some other figure 
So no much choosing on a spot, instead I am planning on winter cover. With the bridge - yes, it is very interesting task to do, but then I would have two apricot trees I am not sure if I need that many 
. Also I think canker may start going up. And eventually may pass the bridge.
I believe on apricots, that type of canker is usually the result of cold damage- most red fleshed J. plums and Santa Rosa plum also get that a lot here. However, I’ve noticed the damage may be more from sudden fluctuations in late winter and early spring than the most extreme cold of winter. This cold front is coming through when trees are likely at max hardiness and trees should be able to easily withstand temps that are actually normal lows for our zones during a winter cold spell.
If that comes from temperature fluctuation, I believe in general unheated cover should help by smoothing the jumps because of the thermos effect. Anyway, yesterday night we put the tarp over the frame and I am going to keep it there till spring. Will see what it will do…
Most covers you’d put on a frame will increase the temperature swings. They are nearly no protection at night unless heated. But on a sunny day it can warm up inside by a considerable amount, 10-50F increase depending on the cover and weather conditions.
Even silver colored you think? Actually, I just realized, that there is no sun in winter where my apricot is growing, sun is too low and covered by the house almost whole day long. So I think I will be OK there…
I checked the temperature inside the cover on sunny day. Outside was around 15, inside it was 36. Looks like it is a lot. But, the thermometer that was exposed to the sun on my deck showed 53! This tells me that branches could heat up as well(after all, they are dark, and thermometer is white). So conclusion is, the cover really changes temperature a lot, but it prevents branches from overheating and makes jumps in bark temperature more smooth and less in amplitude.
