To a large extent, this can depend on the species of maple. What kind is yours? But as far as I know, most maples have very intensive surface root systems, some species more serious than others. You might want to investigate drought-resistant, deeply tap-rooted shrubs. And even then, plan on doing some serious watering over a few years until the things get established. And many drought-resistant shrubs will not do well in heavy shade. You will have to research. The area around large maples can be difficult to keep any plant alive long enough for establishment, let alone shrubs.

dad did it under a HUGE silver maple ... no on green giants ... too much potential ... dig a hole twice as big as the pot ... remove all roots.. replant in native soil ... mulch well.. and water properly ... the real key here.. is that every maple root you sever.. will grow back.. and will grow back into the hole you dig ... you need to get the transplant established.. before the maple gets those roots back in there ... maples are super water competitors ... so you personally have to insure the new stuff.. gets the water it needs ... until it can fend for itself.. back to dad .. he often had to replace one or two.. that simply could not make it to establishment ... there might also be the issue of enough sunlight for them to thrive ... and not get sparse ... potted arbs can be severely root bound ... and that could be a major problem .. if they never grow out of the hole ... see link for planting guide link if .. upon digging a hole... just move over a bit.. if you run across a big maple root ... your new plants do not have to be in a straight line ... ken

I agree with you gardengal, not to mention in my above post I errantly assume the owner will stay in the house indefinitely. I agree with the dwarf varieties. It appears to me that the yard isn't very big #1 so I doubt it is an insane amount of work. Its a huge focal point as it appears to be by the front door, about 12-14 foot long length by 8-6foot down to 0 wide, and a small grouping of lower growing Japanse Maples like a Tukeyama and Waterfall variety grouped together and trimmed once a year EVERY year would be pragmatic. My mom has a 40 year old 8 foot Tukeyama in full sun all day zone 9 FL gulf coast in an area half that size granted we have taken turns pruning it for its entire life. The Sun only reaching the front corner for one hour is a very good thing so I expect if you plant one the plants will reach up towards the sun so i would plant slightly closer to the wall than the walkway. Pad compaction could be an issue so I would be sure to amend the soil when planting. I would also be concerned about prolonged periods of drought as the bed is probably cut off from irrigation. A cheap irrigation design is to get 2 gallon food grade supermarket buckets, attach capped pvc running from the base of the base of the bucket perpendicularly, drill 1/16th in the pvc, and burry the line underneath the trees. Make sure you have a cap for mosquitoes and you can even put an ornamental pot on top or in front of to hide the bucket. Makes a great way to apply liquid fertilizer.

true, a jap maple would be small, but the point is to match what the rest of the block has with a 'regular' green maple. I can post google street view of the rest of the maples, but ultimately what I want is a close enough match with it being a slow grower most importantly. I already texted pics of the other trees to the nursery and asked if they had the same type but I guess they're all so similar that the question was dodged and I was just sent a list of their regular maples. good to know/think existing roots won't matter but there is lots of debate/threads about that. i.e 'trees grow next to old stumps in the forest no problem' but the old root could have been decaying for decades before a tree takes hold near it. The new tree might just root under and eventually past the existing roots is my hopeful theory but I'm not positive. I will still give good caution about planting the next tree here without being able to remove much of the previous' roots.