Look until you find one raised from seed or even a cutting. In addition to possible delayed graft incompatibility there is the possibility of the aforementioned ugly differential between the diameter of the sweet cherry stem and the stem of the Sargent cherry, as well as likely issues with emergent roots and suckers - here in western USDA 8 sweet cherry root-stocks are often a nightmare in parking strips and other turfed or paved areas.

As no-one has followed up this interesting post, I'll give my thoughts. First of all, the quoted hardiness temperatures generally refer to survival temperature, not the temperature when very slight damage occurs. Secondly, this temperature is very dependent on exact conditions and can only be considered a very rough guide. Length of exposure to damaging temperatures, humidity, wind speed,age, stem thickness, protective leaf canopy -- all will alter the result, and can vary over a few yards. Poncirus has developed hardiness by becoming deciduous, by generally delaying its springtime growth even if there is a short warmer period, and by developing bud scales which protect the flower buds as they form. Poncirus hybrids maintain some of these features but to different degrees. I also have citranges which show leaf curl after hard frosts, but I don't think the plant is damaged by this. Some leaves drop later, but are soon replaced by new ones. What is more damaging is a lighter frost after spring growth has started. Even Poncirus new growth can be damaged. I don't think your query about whether 'these plants haven't stayed cold enough overall' is relevant unless spring growth has begun.

Nice patch of tulips there! Excellent shots of the crocuses, Sierra! With the exception of some fosteriana 'Red Emperor' tulips up by the house, ours are mostly yet to come. Laurie, the general gardening wisdom is that, if peonies are planted with their "eyes" (i.e. growing points, usually red) too deep, they won't bloom. If you look at various references, you'll see it recommended that the eyes be anywhere from 1 inch to 2 inches below the ground surface. Personally, I think 2 inches is a bit much, but it would be interesting to hear the experience of others on this. I just (finally) lifted a couple of non-blooming peonies early this spring, that I think were plenty mature enough to be blooming by now, and replanted them with the eyes about 1/2" down... they weren't really all that deep before - probably about 1" to 1.5" depth. Of course, there's always the possibility that a non-blooming peony just isn't mature enough, but I'd had these for some years and had seen very few blooms on the one, and no blooms on the other yet. I don't see any buds on them yet, but perhaps I was too late to make a difference this year anyway.

I found this on a U of Idaho extension page..describes Altaglow as being 20 ft rather than 8... A tall, columnar shrub that grows about 20 ft tall with a spread of 10 ft. The berries are large, white, and sweet but bland. Self sterile, so plant another cultivar nearby to set fruit. Produces brilliant fall foliage and was selected for use in large landscapes. On another site I read it described as having sparse white flowers in spring(this site also described it as having great fall color and being tall). Can't find any info anywhere on where to find it though! Here is a link that might be useful: Altaglow