Most JM's can be grown in zone 5 provided proper conditions can be provided. But I am a little unclear as to what you may be looking for......a maximum height of 6-8' puts the tree into the dwarf category for sure. And most of the dwarf forms are either weeping or very shrubby in habit.

The attached link provides a very nice listing of "dwarf" cultivars. But keep in mind that plants don't read the books and do not necessarily stop growing once they have reached some magically designated "mature" height. FWIW, I know of a selection of 'Mikawa Yatsubusa' that is easily 15' tall compared to the 6-7' it is supposed to grow to.

Here is a link that might be useful: Listing of dwarf J. maples

Thanks for the reply gardengal. When I was referring to not being a dwarf variety I meant that it not be like geisha or sharps dwarf pygmy where they would only reach about 3ft. I could see how I might have confused you though since just about all Jap. maples are (as far as natural standards are concerned) considered as dwarfs.

I was just looking for some cultivars that can withstand being planted in the open and could indefinitely be planted in zone 5 and exposed to full sun (I know most species need afternoon shade, getting leaf scorch etc.. in full sun), while in general staying on the small side as far as trees are concerned.

The cultivars that usually get mentioned when talking about hardy JM's for growing in marginal zone 5 conditions are 'Bloodgood' and 'Emperor 1', but, as Gardengal says, many others are grown succcessfully in these conditions.

There is a nursery in Springfield Illinois called Davidsans Japanese Maples that I have heard good things about, see link below. Davidsan's website has lots of good information on growing in zones 5 and 6, and the listings of maple cultivars are also rated for "area suitability" which might help narrow down the choices.

Here is a link that might be useful: Davidsan's Japanese Maples

thanks mafle, I gave it a short look over and it seems great. Not many sites have a good description of the cultivars specification (which is the most important factor in selecting an appropriate tree). The funny thing is i remember already visiting this site some time back but i never knew it was close to me. Definitely have to visit it since I love Japanese Maples. Thanks again for everyone's help.

-Mike

I wouldn't consider ALL Japanese maples as dwarfs :-) The straight species and a number of select cultivars have an ability to get quite large - 30' is not uncommon. It just doesn't happen very rapidly.

Both 'Bloodgood' and 'Emperor I' are larger growing selections, getting to be about 20'+ eventually. One smaller cultivar that should do very well for you and has many of the features of 'Bloodgood' but at a much smaller scale is 'Fireglow'. This should top out at around 10-12' or so and is very much tree-like in appearance, not shrubby. Most of the other selections that will stay within that 6-8' range will be much more shrub-like in appearance. Or weeping forms :-)

I live in zone 5a, Des Moines, Iowa and my fireglow has done very well. I highly recommend this variety, due to reasonable size, sun tolerance, and midwest winter tolerance. oh and don't forget color.
By the way, I drove 4 hours to visit Davidsans and bought 3 other varieties from him. Davidsan has a passion for Japanese Maples, and it shows in his inventory. What a treat to have a place like this in our neck of the woods.