@mntreegrower. If anyone has experience with this tree on here it's you!

This species just seems like a more northerly, parapatric variant of Pyrus calleryana. What's to keep it from also becoming invasive?

^^^ Aside from the fact that it has been grown in this country since the turn of the 20th century and with no indication of invasive tendencies? That and the fact that it flowers earlier than any other popular pear species and so is prone to frost damage that would prevent any fruiting, especially in colder/more northerly locations. And it also needs a compatible pollinator.

Fair enough, but has it been grown in places where those tendencies could be demonstrated?

According to this website it's not grown in many gardens along the eastern seaboard.

https://websites.rbge.org.uk/multisite/multisite3.php

Longwood has a plant, but only starting in 2007.

Prunus mume and hazelnuts are 'fruiting' / 'nutting' (LOL) most years here, so I would speculate it would have no trouble producing viable seed here.

But it sounds like a valuable ornamental for zone 4 where it's unlikely to become a problem.

"Prunus mume and hazelnuts are 'fruiting' / 'nutting' (LOL) most years here, so I would speculate it would have no trouble producing viable seed here."

I have to admit, I don't understand the logic of how this pertains to P. u. (?) invasiveness potential.

This tree never seemed to catch on in the upper midwest. I don't have numbers, but I rarely see it offered at retail nurseries. There are a couple of clones, which I think Bailey Nurseries and NDSU developed, but neither seems to be especially popular. I did see a nice seedling specimen at Morton Arb and started to seek it out. It was never available where I was looking, which was pretty much all over western WI and eastern MN.

I planted a 'Ure' an a 'Golden Spice' last summer which are obviously fruit trees, but I loved their their ornamental qualities most (great fall color and leaf texture). A pyrus ussuriensis selected specifically for ornamental qualities has got to be a really nice tree

I have to admit, I don't understand the logic of how this pertains to P. u. (?) invasiveness potential.

Because they are early blooming too, probably earlier than this species.

FWIW, Arthur Lee Jacobson says of the species:

"Still very rarely grown for ornament, and valued only where P. calleryana is too cold-tender"

"somebody mention you in a question" - If houzz hadn't sent me an email, I might not have noticed this until late spring.

Why, I certainly have tried Mountain Frost! You have guessed correctly. It's a rather nice tree for sure, but as maackia said, it just has never caught on in the upper Midwest. That's the main reason I only planted a few smaller trial crops of it. I couldn't sell all of them. It's probably been over 5 years since I had one in my fields. If I remember right, fall color was quite nice, never saw any fruit (but the trees may not have been old enough yet), and never witnessed much of any leaf or twig blight. Growth rate here was similar to many crabapple cultivars. They did, however, seem more susceptible to developing trunk cankers than your standard ornamental tree. I don't know if that was a result of Minnesota's often extreme spring and fall temperature swings or not. Your climate is different in its own ways so hard to predict how this tree would perform for you.

Does anyone sell it in your state? A major retailer here in the Twin Cities appears to still offer them in pots on their website and Bailey's still has them in their catalog for lining out as bare root.

MNTG, thanks for sharing your experience with this tree. Do you think its failure to catch on with the consumer was a concern over invasve potential? I’m guessing no, but you would know better than I.

@mntreegrower

I saw 'Mountain Frost' on Fort Collins Wholesale Nursery 's list. I was intrigued, because, as I said I put in a 'Ure' and 'Golden Spice' and was impressed with their ornamental features. 1.5" B&B - 2.0" B&B $235.00 - $295.00. Not a cheap tree (for me).

Also, I planted a Spring Snow a few years ago and it's doing very well and I'm pleased. Don't hate me!

Not a cheap tree (for me).

Not for almost any of us here, I think. Especially because I really question the 'value' of buying large trees in many cases. I think the majority of trees are better off planted as small 1 or 2 gallon size plants with fresh unknotted root systems. The Quercus X procera I got from Oikos as little paper cups have zoomed up to be big 15' trees and I have no doubt have almost caught up with what a big B&B specimen would have done by now. But we are an instant gratification society and large B&B trees suit that mindset.

Granted in 2009 I did make a trip to Colesville Nursery north of Richmond and bought a few large trees and brought them back in a box truck, if anything I regret not buying a couple more. At the time, though, I barely had a vision of what I wanted the garden to be. SO, it is what it is. There was only 1 really large B&B though (the rest of them were large containers and about 6' tall) and it was a species whose cyborg-like roots obvious grew past any restrictions or excess constraint they suffered in their early years! Of course I did cut the burlap and the steel wire hold it on. (It was my Ulmus parviflora 'Emer II')

"Also, I planted a Spring Snow a few years ago and it's doing very well and I'm pleased. Don't hate me!"

Hey, I could never harbor contempt for anyone just because of their choice in trees to plant. The act of planting a tree....any tree (non-invasive, of course).....is a good deed in my book no matter the variety. :)

I wouldn't dislike Spring Snow so much if I wasn't growing and selling trees for a living. That can be said for quite a few other popular cultivars as well. Market demand is out of my control, unfortunately.

$235-$295 is not a cheap tree for me either if we are talking personal use. Do you know of any retail nurseries near you that sell bare root in the spring? If you don't know of any, then you need to become best friends with someone who operates a wholesale nursery and would be happy to "help a buddy out." Of course, bulk quantity ordering is always a potential roadblock no matter what.