Less is more. Avoid the tendency towards "giving it a haircut"...that is, shearing all pendant growth at a predetermined height above ground. that will detract from its gracefulness. I'd only ever remove lowest complete branches at the trunk, and maybe just some "target pruning" along the wall should it become necessary, by which I simply mean to always cut back to a lateral, leaving no stubs, and doing as little of that as possible as well. someone's going to tell you you have to move the plant. I'm not familiar with this cultivar so I'm not telling you that. I think this can work but just use a light touch.

Cut back to a branch or branchlet, my word for a little branch which comes off a larger one. That way, no stubs will be left. The tree doesn't know what to do with stubs and they can eventually serve as "food" for decay organisms, not to mention look unattractive. If you're still wondering, no problem....I have to run but I'll check back tmrw.

I think picture number two answers you own question. "Will the tree as it grows affect the wall?"

If you will notice the wall with the large tree with its roots on the other side of the wall, is already causing a crack. The crack is mid way between the two plantings and at the height of the shortest of the plantings on the right.

Eventually this crack will require an expensive repair of the wall, or the removal of the wall.

Since it appears the neighbors tree has already cracked the wall, the addition of a tree that grows large on your side will only make the situation worse

Haha. Actually that particular brick wall doesn't have a tree on the other side. That crack was from the something else there. The large tree that belongs to our neighbor is on the left side of the patio on the other side of wood fence wall (not shown). So far so good. Their tree has not bothered the wood fence. :)

Yes and no. I'm taking about first-don't do the "haircut" thing along the ground line, so to speak. Then, instead of "working the top", just remove those few entire branches-if any-that will allow for clearance.

I'm not standing there, but if I was, I could clear this up in a hurry. Easier done that said! But the main point is, if you are to shorten up a branch, do so by cutting back to a lateral rather than arbitrarily stubbing it off somewhere. Hope that helps.

OP has started a new thread. Here is the rest of the saga

To your advantage, you are starting this shaping early on, rather than trying to work with an established tree. These are vigorous trees, so it is better to keep up with the pruning maintenance rather than correct after the branches get out of hand. I have not pruned mine much yet this year, so it has a bunch of spring sprouts showing. But I will try to explain how you could try to restrict the size of your tree, without completely destroying the form (shape).

PHOTO 1 shows the underside of my tree. I was pruning towards an umbrella shape that would be increasing in size. So I was removing branches that were growing under others and weeping closer to the trunk; leaving branches that were above, growing in a higher position and with a larger arc.

thank you so much!

furthermkre couldn't I just cut all branches off the backside? no one is going to see lol

Yes, you can. It is your tree, your yard. It won't be "unnoticeable" to any knowledgeable gardener seeing it, though. It probably would not be even a candidate for the worst prune job I have seen. But then, there are images like the one below permanently etched in my brain... :)

Because the tree is hemmed in on two sides it's unlikely to grow evenly all round. The back side will probably grow less and the tree will tend to lean outwards. It will grow thicker on the patio side. So there may not be much that need for pruning around the back.

It's pretty straight forward. Plants need light. The back of the tree will get less light and it will try to remedy this by growing towards the direction with more light. Also as branches grow on the back side they will begin to brush against the fences which will also stunt them.

great! problem (sort of) solved! :D

"So this young tree will grow, according to it's tag, " 6-8 feet both
tall and wide". I've read on other sights 10 feet for these, but our
particular one says 6-8 feet wide It has this amount of space on sides
(between it and the fig and rose tree) and in front we don't mind if it
goes 3-4 feet which its tag suggests (I'm assuming 6-8 feet total, so
that would be 3-4 in *each* direction. Not 6-8 in each direction)."

It's not as if a tree will reach some magical size and stop growing- they grow forever. The estimates (and they are just estimates) generally reflect size predicted at ten years. If you plan to live in that home for twenty you may look back on this entire endeavor with a whole new attitude.

I don't know this tree personally so I Iooked it up. This link says you can expect 20 - 25 ft high and 10 - 15 ft width. Birch info.

The size info purports to be about the cultivar Summer Cascade.

I walked into this at a (former) customers garden - I honestly wept to see 200 years of yew butchered so gracelessly.

I believe this type of tree would need to be staked and specifically trained to reach that type of height. Left to its own growth pattern, it only gets taller by the height of the arching branches. Although, I admit there was one rogue branch on my tree that went straight up, but I don't know if it was a revert to the original type, or something that would produce weeping growth. I removed it to maintain the weeping form, and because it looked very much out of place.

cearbhaill don't all trees have some kind of genetic predetermined height cap off though? otherwise wouldn't the trees be rivaling the tallest city buildings? I'm confused by how tall this tree will get. It says 6-8 feet by 10 years. isn't that it's approximate size then? I know it keeps growing but I'm assuming it won't be by leaps and bounds more than this or why even include that tag at all? :D people would just expect all trees they plant to end up 25 feet and wouldn't no one plant trees in their small gardens then? but some definitely don't. we had a Japanese maple in our yard for 30 years that never went above 15 feet. without being staked, couldn't this tree stay around its intended size?

midorit:
"don't all trees have some kind of genetic predetermined
height cap off though?"

In a word...no. MOST trees keep growing for their entire life expectancy. They aren't like people, that stop growing shortly after puberty. A few trees slow down when they reach a certain size...but just as many Trees accelerate growth as they get older and bigger. You'll find lots of people here grind their teeth at size estimates on tags, which are largely meaningless. The estimates are provided because inexperienced gardeners want them and no one is telling the nurseries they can't.

Small trees are usually either short lived trees or slow growing trees. Fast growing trees are usually either short lived or ultimately become HUGE.

Deciduous trees can be pruned, but that's very labor intensive.

In theory, people shouldn't garden with a single moment in time as the objective. They should have several points in mind, a mix of faster growing things that will look good soon and slower growing ones that will look good down the road. That's not how other home improvement projects work, so no one does this.