I would be interested to know too. I have both, purchased from the same supplier maybe 8 years ago, but the writing on the labels faded and I forgot which is which. The ones I have are clearly different from each other, with subtle differences in the leaf colours, different twig colours and, most notably, one has larger leaves than the other - I just don't know which one!
I have both about 7 years old in the landscape and i live in usda zone 7/8 (right between the 2). Both are in similiar environments about 50% sun and 50% shade. Murasaki kiyohime is much more vibrant and pretty in the spring with purple pink edges that only lasts for a few weeks compared to kiyohime which also has pretty edges but not as sharp of a contrast. Also kiyohime grows much denser if that is possible and appears to be a little more aggressive growing at least to this point. Kiyohime is the densest (word?) japanese maple in my entire collection and this makes it interesting in form even in the winter, dormant months. Neither are very good in my opinion for fall colors and both appear to tolerate the heat and sun well with little leaf burn. Their is little to no difference between leaf and color midsummer. Hope this helps. Enclosed is Kiyohime spring 2010 picture. Sorry no Murasaki picture. Dont have good closeup. Justin
Thanks, I brought both today 2 gallons. The Kiyohime is mush for dense and tighter growth on all the kiyohime and Muraskaki I compared at the nursery, the color of Kiyohime is also darker green. I don't know if it could be due to the shade and placement of the plant at the nursery. The ones I brought will be kept side by side and I will study and make comparsion. Leaves shapes seems idenital. very hard to tell the difference. Thanks so much for the discribing in details. Will update with the differences I will notice as time goes by.
I have both which are in a large form about 4" caliper. I have found the Murasaki has a much more vivid color in spring with the dark purple edges. Since i bought the trees in mature size I can not say completely that there is a different growing habit but the two trees do look different in form. The Murasaki seems to have a lower growing habit which can make it a wide tree. I had found one Murasaki Kiyohime in Oregon which was 14' accross. Currently my Kiyohime does have a darker green leaf. I have had more early season damage on my Murasaki kiyohime.