Why don't you plant columnar apple variety instead?

usually, people spread the tree's limbs for a few good reasons including forcing a tree to create fruit buds sooner and increasing air circulation through the tree and letting sun light in, both helping reduce disease issues, etc.

what you want to do is opposite to what should be done with an apple tree.

The columnar varieties will do so-so in my growing zone. I was hoping to use a variety that grows well in Zone 9, but prune it to grow like a columnar.

I don't know the answer to your question but suggest using a spur producing variety verses a tip producing variety, as you will likely prune all of the flower bud growing tips off.

Thank you for that. I would have never considered the difference in spur vs tip.

Thank you gardengal48. I've looked at the article. Now I just need to do a bit more research.

check out plantsmans corner on you tube. He is a very experienced nurseryman and does great videos on summer pruning apples as small step overs as well as pruning them for columnar and archways. You might have to look a bit to find the right video, but his information is great. I plan on doing step overs, as this is the only way in my cold zone that I may get some different and less hardy varieties to produce, as they will get total snow cover during our cold winters.

I'm not quite sure what you mean by columnar, but I do know it is possible to to train them up against a wall, or the side of a house, so they have a very flat appearance, which works well for a small garden.

Espalier!! That was the word I was looking for! Here is a couple of links that might be helpful if you want to look into it:

https://en.wikipedia.org/wiki/Espalier

http://www.motherearthnews.com/organic-gardening/espalier-apple-trees-zmaz93onztak.aspx

Good luck!!