Scott,
Thank you, Scott. Very possible. Yes, all damage started from the top.
We had temp at 31F during bloom and again a week later. With this much damage, I should not rely on the critical temp chart too much any longer.
Like I said the damage has been over 90%. So much so that I wonder if it is worth it to protect the remaining against birds.
@2manytrees,
As you may know, one of your trees, the one that is sprouting from the rootstock will need to be grafted on with a named variety (or two or more). I’ve found grafting cherries easy.
I see if @speedster1 can chime in. He is in W. Virginia. I think he grow or have grown sweet cherries.
I live in the Mid Atlantic but have only ever planted cherry trees on G5. I’ve never tried Colt. I just wanted smaller trees. I’ve not had the greatest luck with cherries here. They are the biggest magnet for Japanese beetles in my orchard. Not overly vigorous either. My Black Gold on G5 died with no explanation. I still have two grafted cherries on G5 but frost wiped out this year’s crop.
Is it worth grafting to, or should I just remove the rootstock and start new with something else?
You mean a new sweet cherry tree. If so, you ask the wrong person. Maybe, you can try sour cherry like Monmorency. If it were me, I would be done with sweet cherries. 
The simplest and fastest in most cases would be planting a new tree. Having said this you can certainly graft a new scion to the rootstock. If you have space you could do both.
Also you were asking about Colt rootstock, I have seen a couple of references stating it is not cold hardy. However, they don’t say to what actual zone the rootstock is hardy to. So it’s difficult to say if Colt would work for you. It’s seems Colt is a fairly common roostock in England and in the Western United States (California?). So you might want to look in to this before buying a tree on Colt rootstock.
Maybe a few of you could help me out so much information it’s overwhelming. I’m in zone 5A New England and just starting off with Cherry and Plum trees. Is there a book or something that you would recommend to start to learn about spraying and such. I was given quite a Variety if stuff in trade from a job. Bare roots to trees ECT. Several different varieties. Bing,Rainer,Juliet, and a few others. Everything is in containers most are 3-4 feet tall with a few taller. Wanted to keep growing in containers for a while until we get land cleared to plant. Any help at all would be greatly appreciated…
Stephen,
Where the zone 5 are you in New England, VT, NH, ME or MA?
You pick the pickier fruit to grow, plums and cherries. It will be a learning curve. For instanve, Bing cracks too much for rainy NE and Rainier is not hardy enough for.zone 5.
You grow them in pots, that can be a good thing (can be protected against rain) or a bad thing (some cherry rootstocks may be too big to be in a pot) and many more.
Someone else may be able to help you with books. I just look up the Guide category of this forum to learn about spraying.
For low impact by Scott Smith
And for full impact by Alan
I like to spray indar right before the blossoms open. I’ll do a spray of Imunox earlier when the temps warm up. After all the blossom are done and no bees are in the area I do another spray of indar mixed with a strong dose of triazicide or imidian. That has worked well for me. Imidian is the strongest but it’s not meant for home orchards with it’s hazards.
Yes, cannot use Imidan in a residential area. Triazicise is a hit or miss. Sprayed it for 3-4 years, not working consistently well.
I try to find a cheaper version of fungicide that is in a different class from Indar (and Immunox) to avoid buliding resistance. Chlorothalonil is in a different class but has a long PHI so can’tbe used after shuck split.
Thanks for the reply!! I’m in Vermont. I do have containers up to 30 gallons and can move them to hopefully they will go into the ground and not need pots…But I have a chance to pickup a good size greenhouse pretty cheap so maybe they will go in there for better control if I can keep them smaller.
Rainier can work here, Bing, maybe not so much. However, Cornell had a long-term breeding program to improve choices for the northeast, and of these, I believe the most grower friendly may be Whitegold.
Conditions in spring and site are very important. If site isn’t very open with plenty of eastern sun, and even all day sun, wet springs can rot the flowers entirely or most of the fruit later on. If fruit remains until late spring it all depends on conditions a week to 10 days before ripening. If it’s dry you are in luck, if not, you may have to have fungicide on the fruit active right through ripening and will still get lots of cracking.
In addition, you will likely have to net your trees to benefit from the occasional great harvest, or your work will have mainly served your feathered “friends”. As satisfying as having your own cherries in June may be, they really aren’t much or any better than store-bought, IMO.
All that said, I still have a couple of trees in my orchard. Their crop was frozen out this year- but then, all my tree-fruit was besides apples, figs and mulberries.
@Alan,
I’ve read that Rainier does not do well in cold zones. The OP is in 5a. Are you sure it could produce in 5a?
No I’m not, I’m only speaking for my region which is a little warmer, but we do have test winters and Ranier survives -20 F, apparently. It’s also relatively productive and precocious for a cherry- if it survives my “hunch” is that it would be just as productive in 5a.
However, I’m not offering it in my nursery anymore and stick with Cornell varieties.
Doing a search, Stark’s and others list it as good for zones 5-8
I just re-read @clarkinks’s thread about sweet cherries. Although the article is for commercial farmers,it contains good info. In the article, Rainier was not cold tolerant. Bing cracks too much.
Also, I don’t really trust Stark Brothers these days judging from input from several members that deal with the company in recent years.
My rainier has survived -30 and a lot of below zero weather. It’s my most productive tree except this year it got froze out in the spring like most other fruit.
I’m in Oxford, Michigan.
Lucky you. Michigan is few friendlier states for sweet cherries beyond the west coast. Challenges go up for further east like us.
Glad to hear your Rainier withstood subzero for you. Do you have a large body of water moderate your climate?
Michigan cherries are up north on the western shoreline of Lake Michigan. Lake Michigan shorelines provide an excellent cherry environment. They also grow good on the other side of the lake in Door county Wis. I’m a couple hundred miles from the cherry belt in Traverse City Michigan so not much advantage with the water warmth in the winter and spring. I’m actually in a small cold spot for my entire area. I hold snow longer and get more of it. Kids in town when they came to birthday sled parties were in disbelief that we had snow because it’s all melted a mile from us. Even the guys at work roll their eyes thinking my climate is not any different that theirs. Everyone on my road says that only the ones that live here will really know. We live at the top edge of a small plateau but it’s just enough to make it change the weather.
All my cherry trees grow good but Rainier grows like crazy! It grew five foot one year. I wish I knew how to prune them better when I first got them. I would have done the KGB method.