hey ja ....

i like your transplanting graph ...

it does equate with my z5 MI ... wherein the default is.. move everything in april just after the ground thaws for me ...

i can also get away with mid sept thru mid october ... in MI ... though i cant say i have moved anything you list in red at that time ...

i also like that june is basically red ... and i would sum that up as .. because the plant doesnt have time to re-acclimate .. get those roots pumping .. to be ready for the real heat of summer in july/august .... besides the fact that the trees are leafed out.. and that just complicates life more than need be ...

i dont know about your maple question.. lol.. i just liked your graph ...

ken

saw it just north of St. Cloud, MN, but was absent from the collection at Absaraka, ND. Not sure if the later meant it died out or if it was never planted. Either way, hardiness is really good.

Honestly, I walked away less than impressed. In a world filled with choices, at some point you either have to have them all or admit that...well, the differences aren't always all that great, and that's really what I thought: that there are simply too many choice out there to choose from, and this one doesn't really offer any clear cut reasons to plant it.

Compared to A. griseum and A. triflorum: hardiness equal if not greater. Faster growth rate, almost a little gangly, but that could have been a factor of pruning or growing conditions. Fall color potential, but not consistent from seed grown stock. and there's something sticking in the back of my mind about size, but when growing stuff north of the Twin Cities, the weather usually holds stuff in check.

.02

Ken, thanks for the compliments. Yes April seems like the time to do everything in the garden. That's the problem.

Strobiculate,thanks for your maple comments, that's what I was looking for, peoples opinion of trees they have seen.

Jim

Here is a link that might be useful: My blog site

ja-gardener,
There are two large trees at a local nursery that were brought in as B&B trees. They have been there many years, as I assume very few people know what they are. I have watched them for the last 3-4 years. They have long ago rooted into the surrounding material, and now I would not know how you would get them out and plant them. These two trees develop early fall color pretty consistently every year. Kinda of a coppery reddish brown color that is certainly pretty, but is not in the same realm of knock out color as many other trees. These two trees have survived many many days 100-110F for many days the last couple of drought heat ridden summers, with no apparent issues, though they were receiving supplemental watering at the nursery. I personally like the look of them, like the fall color, and the apparent hardiness of the tree. But I'm not sure that allot of people would notice them.

What can be surmised from the above is that they are very heat tolerant, if they have adequate water, but do not know what "adequate" is. The trees seem to aggressively root into the surroundings, but on these two trees, there are no sign of surface roots. They apparently develop early fall color that is pleasing, but not knock your socks off spectacular. The color is however a welcome variation from mostly red/yellow fall color of most trees that are planted for fall color. Nor have I seen seed on these two trees. They are a rare tree that has rather little about it on the internet. And of course cold tolerance as stated.

I very much like these two trees in the nursery, that I would certainly welcome if we had more space. However I likely would not pick them over our triflorum or our griseum's. So perhaps 1-2 mixed in a larger landscape, but not at the expense of triflorum or griseum.

TIFWIW (Take It For What It's Worth)
Arktrees

Based on its native range (Korea, Manchuria, Russian Far East) it's probably quite cold hardy but probably not very heat & drought tolerant. We planted a few a couple years ago, and based on my observations so far it doesn't appear to tolerate dry conditions (non-irrigated) very well. Those in irrigated locations have grown well, however. As mentioned above, it colors early in the fall - a soft red here. I'm guessing strobiculate is correct that it will grow faster (& larger) than griseum or triflorum. Doesn't have the marketing appeal of those 2 species, but still a nice tree.

Had Acer M. in a pot for a few years. Leaves tended to dry by late summer. This pretty much prevented much fall color. About 3 year ago I planted it in the ground. This corrected the leaf drying. Moderate growth although someone decided to top the tree. I agree fall color less consistent than acer griseum but in a good year similar solid, even vibrant red. This year was very good. Nice less common maple. Interestingly, after about 5 years my three-flower maple (Acer Triflorum) has yet to show much color and the brown leaves hang on well into winter.

Neighbor has a Manchuria Maple. We live in Chicago area, 35 miles west of the city. The tree is now (October 9, 2020) a gorgeous red, 25 feet tall, oval. No special care needed, though it is planted at the edge of a protective stand of woods. full sun not needed. Water average. Soil clay with base ph. An amazing tree.

I've grown all four maples in Section Trifolia, and this one has been the best performer. It is fully hardy through z4 and probably into z3. Nice habit, clean foliage, and beautiful fall color. The only negative is how seldom it is seen in the nursery trade.

The small number that we planted for street trees (about 10 years ago) are growing reasonably well, although they have been relatively slow. This photo of one of our trees was taken in mid June of this year. I'll have to check on its fall color status sometime this week.