These plants are thought to be very similar. In fact some believe they are synonymous. I am growing both and have been observing them for myself. I grow 2 'Aka omote' both are 4-5 yr grafts and one 'Ruby' which is a 2nd year graft. In the photos we can see that the leaf shapes, at this point, are quite different (more/less orbicular) in a somewhat subtle way.
I don't draw conclusions about the red shading in either plant because the sun exposure is slightly different and both plants seem to bronze up rapidly when moved into an exposed location. Also the new growth shown in the photos results from a super rainy month or so here in Philly. All plants are in pots and have had a dose of nutricote.
I communicated with Norm Jacobs at Arbutus Garden Arts, a retailer of 'Ruby'. Norm passed along this info:
Ruby/Jim's Red has almost exactly the same size/shape of leaf as Aka
Omote, but the plants are different in the color-cycle of their leaves,
and even more different in their cultural needs. Aka Omote's leaves
open like a parasol, while Ruby's open in a more conventional form - Aka
Omote begins maroon and keeps that blush until the heat of summer, then
puts on a vibrant red and yellow display in the fall. Ruby opens deeper
black/red and evolves toward a brighter red, only bronzing in July or
later. It has less brilliant fall color than Aka Omote.
Culturally, Aka Omote performs best in a more shady situation - morning
sun, then shelter for the rest of the day. It will burn in full sun. Ruby can be grown in full sun. Both do best with average moisture -
possibly owing to some A. shirasawanum in their genes. While neither is
fast growing, Ruby is the more vigorous. The original seedling is about
eight feet tall and wide in about 20 years. Jim is Jim Schmidt of
I'm interested in anyone's thoughts and observations. 'Aka omote' is a favorite of mine and it could be that 'Ruby' too is choice.
I just bought on Easter a Acer shir 'RubyRed' from Robt Jamgochian at Mendocino
Maples who is a good plantsman and produces a good product. I believe 'RubyRed'
is the same as Ruby/Jim's Red. Ironically I had bought an 'Aka omote' also from
Robert in July 2008. When I saw your thread just now I walked outside and put
both plants together and studied them. They are young plants which look too
similar for me to clearly differentiate with this little history with them but on a prima
facie basis they look like different cultivars. I just called Robert who is still evaluating
these 2 cultivars having had each for only 2 years but he told me in reply to stress
to you that his experience is that RubyRed new foliage has significant pubescence
on the new unfolding leaves.
Another observation surprised me, 2 of the new leaves on Ruby have foreshortened
center lobes like a witches broom which I do not see on Aka but this could be just
some aspect of their juvenility.
I can't say much to Ruby, but I will say that Norm knows the maples he grows and is pretty accurate in his descriptions. I have been to his nursery and he is farther north in Oregon than some, but his location has a lot of good sun and is pretty dry in summer. He only grows maples that are survivors.
I have had Aka omote since Norm first offered it, maybe 4 years ago and with some care, it is getting some good size on it for me. It HATES the hot sun and anything about summer. It holds is "red" (that is a stretch) for a very short time and greens up very quickly. For me in southern Oregon, it behaves more like a circinatum than a japonicum. It also is subject to some winter tip die back that is uncharacteristic for japonicums that I am familiar with.
The issue here is that aka and ruby imply red and these are not red japonicums. They have exaggerated red blush or leaf color early in the season, but this is common for Japonicums. Just like with Shiraswanum, red has really not been introduced into these maples--they are still green and to get them to perform otherwise is very wishful.
Negative aside, I love my Aka omote and I look forward to getting Ruby when I have the chance. Once can never have too many japonicums--you just have to make space for them as they get darn big....not for limited space.