Crimson Queen and Red Dragon are mounding dissectums that will be much wider than tall. CQ will be the largest and I would give it at least 5-6ft. The Red Dragon you could 4ft. Those are miniums and may/will require some pruning to control in the future.

Seiry is an upright grower shat is as wide as tall if not just a bit wider. It is very willowy in youth. It can grow easily to 15ft tall. It is one of the most beautiful maples in my opinion. I would want 7ft from the house, but again that would be the ideal minimum. Seiryu does not lend itself to pruning to contol size as well as some of the other maples. It is best left to grow naturally.

Orido nishiki will be 8-10ft tall, but can be taller. It will not be quite as wide as tall so you could go 4-5ft from the house.

Now, I rarely follow my own advice and plant closer to the house, you just have to be ready to control them and in doing so, you will not see the form maples can achieve. The other option on the Seiryu for example is to plant close to the house and prune the back side of the tree, thereby it grows away from the house. This can work and is done often--not ideal but if kept up it can be tasteful.

MJH

MJH
thanks for your informative feedback!
Jim

Japanese maples have fibrous roots so I don't think you have to worry about them damaging your sidewalk or foundation, if that is a concern. The main problem is that most JM varieties tend to spread, some wider than they are tall -- such as most of the dissectums. JMs that are supposed to have more upright habits include many of the various strapleaf or linearlobum varieties such as Beni otake, Villa taranto, Koto no ito, Red Pygmy. These are some of my favorite JMs with fine texture, good leaf color, fall color and form.

Japanese maples have fibrous roots so I don't think you have to worry about them damaging your sidewalk or foundation, if that is a concern. The main problem is that most JM varieties tend to spread, some wider than they are tall -- such as most of the dissectums. JMs that are supposed to have more upright habits include many of the various strapleaf or linearlobum varieties such as Beni otake, Villa taranto, Koto no ito, Red Pygmy. These are some of my favorite JMs with fine texture, good leaf color, fall color and form.