I think I suggested this in one of your other posts, but I love Heptacodium. Species might be too large for that spot but there are two more compact selections on the market: Tianshan® and Temple of Bloom®. This plant is almost universally labeled as Zone 5, but my observation is it does well in Zone 4b as long as it is not on really exposed sites in the winter. Even these more compact versions can be limbed up to be a small multi stemmed tree exposing the peeling bark.

Since you're looking for a major foundation tree planting, don't choose anything that is not fully hardy in your zone. I love Heptacodiums, but if it's not fully hardy, don't choose it. Google small trees for zone 4 and make your decision. Or consult with a good nursery (not a big box store.)

I've done a lot of Googling and looking around at smaller trees. Seems Zone 4 is rather limited. I've seen so many tree outgrowing their space close to homes and I'm nervous about a selection, besides!

One I forgot about that was on the U of M extension website is a Jade Butterfly Ginko. That might be promising. Anyone with experience growing this?

I expect what you are looking for is more of a large shrub than a small tree. As you are finding out, 'small' trees are actually fairly large plants. OTOH, something like a common lilac is more the right size.

Maybe take a look at Betula nigra 'Little King'.

There are many large shrubs, lilac, Spires, forsythia, etc that are very attractive. I have seen lilacs that have grown to 10 or more feet tall, Spriea about 6 feet. While left to grow they can take over the area, but that is what lopers, hatchets, and Bow saws are for

The Kousa dogwood tree is the perfect tree for your spot but there is a catch, some web sites state zone 4 https://www.gardeningknowhow.com/ornamental/trees/dogwood/growing-kousa-dogwood-trees.htm 

and then others state It's a zone 5 tree.

People on houzz https://www.houzz.com/discussions/2020807/any-zone-4-success-w-cornus-kousa

planted it in zone 4 and said they had little trouble.

When you say southern minnesota how far south? I've seen many zone 5 trees growing in St. Paul like the Bing cherry, Bartlett pear and red delicious that are decades old so if you live any where south of the twin cities think about it. Nice tree.

I tried all of the trees I listed 20 miles north of st. Paul and lost them all, the red delicious lasted 7 years until a frigid winter took it out. I was considering a kousa for the same application of yours, south facing but I looked up the Betula nigra 'Little King suggested by maackia and liked it. I'm going with the birch, I love river birch trees.

My kousa dogwood would be MUCH too large for that space!

Talk about marginal, Cornus kousa. Anyway this is why I love Heptacodium. Madison in October. I've had in my yard for 8 years just south of MSP without issues. I know of older specimens around town.

I think a tall, narrow, multi-stemmed birch would look good in that spot, pulled a little farther from the house.

Serviceberry

I really love birches, but I do have three already. I only recently learned of serviceberry. I saw one at the greenhouse just a few days later and they are beautiful. They look like they can get quite large, and frankly, I think they are pretty enough to warrant a spot where they are allowed to to do so.

Kousa dogwood - is this the same as a pagoda dogwood? They look similar. I had 3 pagoda when I moved here and lost them all within the first three years. Now they are popping up all over under my silver maple. I did think (and am still thinking) of plucking one and using it in this spot.

I am two hours north of the Iowa border, in the Minnesota River Valley.

Not to buck all of your suggestions, because I very much appreciate the knowledge on this forum. But the more I look at the jade butterfly ginko, the more I like it. I look at one in person yesterday, and it's a lovely tree!

Pagoda dogwood is Cornus alternifolia and it is native. Kousa dogwood is Cornus kousa and it is of Asian origin. In person the flowers are quite different because pagoda dogwood doesn’t have the large petal-like bracts.

Don’t plant Kousa dogwood in an area that gets much below -20 because they will get periodic winter damage IME. I have two and they can look fairly crappy for several years after a bad winter, and take a lot of pruning to get them back in shape.

There are some nice small cultivars of crabapple which have spring flowers and late summer into winter fruit. We enjoyed watching the birds come to eat the fruit as added winter interest.

Consider some of the bigger cultivars of Hydrangea paniculata such as Quickfire, Limelight, or Pinky Winky.

And for the area By the meter that gets walked on, think about a set of stepping stones with a groundcover such as thyme, with the shrubs planted far enough on either side to allow walking space.

About 6 years ago I wanted something different and looked into a ginkgo tree, loved all I read until they said they drop messy seeds in fall that smell like rotting flesh. I didn't know about the jade butterfly ginko until mentioned here, but how do they sex a tree to know it's a male? I wonder if this dwarf ginkgo has the same problem with root knot nematodes as the full size tree. It is good for zone 4b so that's a plus.

Article in todays paper about this. Sounds like a limited supply at garden centers this year.

https://www.monrovia.com/plant-catalog/plants/5936/velvet-viking-japanese-maple/

I agree. Japanese maples are iffy in zone 5 and not recommended for zone 4. And they are too expensive a plant to experiment with :)

If you want something Japanese maple like, look at the Korean maple hybrids. A cross between Acer palmatum and Acer pseudosieboldianum, these have the size and appearance of a Japanese maple but with the increased cold hardiness of the Korean maple.

Sorry, I've been dealing with some computer virus issues or I would have responded earlier. I actually bought a Velvet Viking earlier this year. I met an avid gardener at a local greenhouse, and we were discussing Japanese maples. We have both lived in Oregon, where they are everywhere.

I was looking for the Ice Dragon, and he was telling me they had been there, but sold out right away. He told me about the Velvet Viking, and said his friend north of the Twin Cities had success with it through three winters, one of them quite severe. Two days later, another garden center posted on social media that they had them. I called and paid for the last one over the phone. I've done a lot of plant chasing this year.

So I guess I will report next spring on how it is doing.

I'd never considered it for the east side of the house, but that's a project I decided to do just in the last couple weeks. I like the idea. The one I have will stay where he is, but the east side would definitely be a more protected area.

Kevin, I just noticed your comment, and I was wondering the same thing! I've heard they are beautiful, but smelly, trees! The jade is so pretty. If it has the same problem as the others, I'll wait until I have room for it away from the house.

In general, ALL named forms of Ginkgo biloba are males. If you do any research, every single source or reference for 'Jade Butterfly' will indicate it is a fruitless male.

Backstory on Velvet Viking

https://m.startribune.com/new-minnesota-hardy-japanese-maple-was-first-discovered-in-a-twin-cities-yard/571217812/

How did the Velvet Viking do for you? Did it survive the winter here? I’m south of the cities in zone 4b and I just bought one.

I didn’t even think I needed to worry since it’s zoned for 4 but now I’m nervous after posting in my gardening group 😫