Like many of the ornamental Prunus species, quite prone to diseases and a few pests, therefore not overly long-lived or with extended attractiveness. Looks best the short period of time it is in bloom. Can often produce fruit which is edible if not particularly tasty.

You're too cold for Japanese maples or Cercis 'Forest Pansy' and purple beech get huge. What about a crabapple? 'Thunderchild', 'Perfect Purple' or 'Velvet Pillar' should hold their purple leaf color well.

Hey Gardengal! Thanks for the thoughts. I am considering a few crabs as well.
Purple beeches are sold here, but not widely. Most of them are coming from Monrovia, who is known for zone-pushing. Part of me wants to try one, but not at $100 a pop!

And you're correct.... Japanese maples are not hardy here. Some can grow them in very protected microclimates, but they are more toward the city, where I'm in the outer suburbs.

Only purple plum tree that might be hardy is 'Newport', which actually originated in Minnesota. That and perhaps 'Big Cis'. 'Newport' has a better, more picturesque growth habit than the purple-leaved cherry plum cultivars but is not very showy in bloom.

There is also the purple-leaved chokecherries.

Emb mentions the "Canada Red Cherry", and that could be a reasonable option for you. Certainly hardy enough. I've had two for years and while I've frequently cursed my decision to plant them-lots of suckers from the roots-they have done very well and only now, after thirty-some years, are succumbing to black knot, an unstoppable disease of cherries, plums, et al. Foliage starts out green in spring and goes to a very nice purple throughout most of the summer. Birds keep the fruit under control in mine, although some do make it to the ground and sprout. I was quite surprised one day last year when, upon popping one of these fruits into my mouth, I learned that these little fruits can actually get pretty sweet. would not have thought so, and maybe there is seasonal variation on that factor, but that's not why you'd be growing it anyway.

+oM

If a wide, relatively tall bush would do the trick, look at the dark-leafed ninebarks/Physocarpus such as Coppertina or one of the ones with Wine in its name.

Pplums are in my yard here in z5. They were great until about 4yrs ago

When we had a nasty/cold winter. A lot of dead limbs, pruning. They are growing back though. Maybe because we keep them watered.

We live on the side of Mt Taylor at about 5000ft. Desert.

The trees are about 30yrs old.

1990 winter damaged certain cherry plum cultivars here also - large sections of dead twigs can still be seen. That is why 'Newport' or perhaps one or more other, equally hardy kinds would have to be used in MN. But if the rather nasty black knot has become prevalent on Prunus there probably no kinds can be planted without eventual failure.