Here is another Acer japonicum that I have been working with. Acer japonicum 'O isami'. It will be a medium sized tree with large orbicular leaves. It will grow in full sun and show yellow/red/scarlet in fall. These maples were grafted in the summer of 2002 and the pictures were made in June 2003.
A.j. 'O isami' Here is my Acer japonicum 'O isami' in a smart pot and it appears to be growing on quite well. Photo made 4-14-04.
Strong vigorous tree to 20 feet depending on climate and culture. Large orbicular leaves, tapering ends of the lobes are deeply notched. As with most japonicums, the fall colors are outstanding.
Here is a photo, made 11-20-04, showing the yellow fall color of this japonicum cultivar, 'O isami'. The dissectum in front is 'Edgewood's Golden'.
Acer japonicum 'O isami' - Washington Park Arboretum, Seattle, WA. Photographs taken in the shade of the Woodland Garden on October 15, 2002.
Here is a Aj 'O isami'. It has great dark purple/ black fall color leaves. It is a bit of a crossdresser this year since half of it is in fall color and the other half is still green.
Well, the bad news is the tree in the posting above did not make it, it is now going to the burn pile. I have have a second one and this year the tree is turning its fall color in August.
I can see why Daniel Mosquin described this in a 2007 POTD posting (really on 'O-taki') as one of two "downy" Japanese Maples in the area. These are at the UBCBG Asian Garden, along Upper Asian Way, past Kingdon Ward Way. These samaras were begging to be photographed. I was checking google to see if the "I" in "isami" would be upper case (edited: never mind that I can't read - it's clear on the tag), and found four different spellings in the first four hits, and then two more. The UBC Accession tag writes it Acer japonicum 'O-isami' (with a hyphen), so I did a search here on that and did not get a hit, only finding this thread by browsing.