I have an accidental avocado tree growing outside (not in a pot) that has so far survived 4 winters in zone 6 and is now 7 feet high. I don't expect it to fruit, and I am very surprised every year when it leafs out. It is in a protected area right next to my house on the west, and just past it is an old fashioned well structure of the wishing well type but it is a real well with real water in the bottom. This house is of stone, built in 1925 and the walls at the bottom are close to 2 feet thick. The ground to the south falls away steeply, so cold air does not pool in this area. All of that probably has a lot to do with the survival of the tree. It has gotten down to zero F in the last couple of winters but that hasn't happened often or lasted more than one night. I have not done anything to protect this tree such as wrapping it. One of these winters the temperature will go down far enough that the tree won't make it. But, at this point it's an interesting anomaly. This is in the most southwest corner of Pennsylvania.

wow.. where is this.. it flashed me back to visiting busia in detroit in the 60's ... its a war zone now... i dont know why i ever went back to look ... anyway.. apparently i digress ... no tree really magically stops growing at some preferred height. .. its all about how long to get there.. and how far past ... i would not put a tree next to the garage.. there just isnt space for anything greater than 6 feet ... with a foot to spare on each side .... i would go with a tree dead center in the bigger plot ... and some shrubs down by the garage .... there is a variegated norway maple ... that has remained rather small for me .... but it might not let you garden under it in 20 years .... i know others have many good suggestions.. i just wanted to chime in an thank you for the memory flash ... to simpler times.. take care ken Here is a link that might be useful: link

Acer palmatum 'Ryusen' (AKA Ryu sei) is a japanese maple with an extremely vertical weeping habit and palmate(not dissected) leaves. With the right training and pruning, it can be formed into a narrow pillar of cascading branches. Branches have to be staked up to the height you desire. This is a high maintenance tree, because its branches grow quite fast for a japanese maple, so its skirt will have to be trimmed regularly unless you want it flowing out in all directions at the bottom. If you want something low maintenance, Helmond Pillar barberry is a good looking option.

a few years ago I successfully grew Chicago hardy figs in Zone 5. it was my first experience with figs, and they tasted amazing! There are better tasting figs out there and there are a few different flavor profiles you can get with Figs. If in the ground is necessary, get the Chicago hardy, know it will die to the ground each year, and it may not show new growth until May/June from the roots. If you can keep it on the south side of your house, you will likely have even better success. If you are willing to look after pots and move them into the garage or an unheated shed for winter, you could grow a whole slew of different figs.