Hi
@Rafael Najmanovich ! Yes i have about 25 cultivars, and this number should increase dramatically next month if all goes to plan.
+1 on what
@sorce said. I have 4 Kashima in bonsai pots, hundreds of seedlings, and a few big trees in big pots, none of them are on the same schedule!
as for bloodgood in particular: one reason why this cultivar (for upright) along with the red dragon (for weeding dissectum) have become
the cultivars that all of our big garden centres in Quebec sell is because of their late opening. When placed in a landscape, this late opening is what saves them from our late frost!
by contrast, even though they are also rated for zone 6 on paper, there are cultivars that are sometimes said to be more appropriate for warmer climates, such as seiryu, sumi nagagashi, and sango kaku -- all of these budded out very early for me!
So although the trees don't follow any pattern in particular, as
@sorce noted, you can make educated guesses if you're familiar with the cultivar. This site has a lot of people sharing first hand experiences with a wide range of cultivars, usually in the context of landscape gardening:
https://forums.botanicalgarden.ubc.ca/forums/maples.9/
Vertrees lists a number of japanese publications that discuss the origins of certain cultivars in japan (dating back to 1600's). Knowing where a certain cultivar came from in Japan would be very interesting information, but my japanese is not advancing as fast as I would like!
there is a guy in south-east quebec who "crosses" korean maples with japanese maples (although he couldn't really explain what he meant...) and this makes them much more resistant to late frosts (landscape stuff, massive leaves most of them)
