Is there any reason why you can't mix the maple leave and the cherry blossom on a tattoo?

Maple leaves are associated with Canada and the cherry blossom is associated with Japan. So, if you are a Japanese Canadian, this may make sense, but there are probably better representations of your culture available.

A tattoo is a very personal thing. If you want to combine symbols that mean something important to you, there is nothing stopping you. I do recommend you work with the artist to get an esthetic pleasing design.

First off, in Japanese tatto the maple would be that of a Japanese Maple Tree. The reason you dont usually mix the two in one tattoo is because they serve different purposes. They relate to the different seasons. The japanese maple leaf is more often associated with the fall/winter and the koi fish travels up stream in the fall. It would make sense to have maples leaves with a koi fish tattoo. The cherry blossom is most often associated spring summer and are often incorporated into dragon tattoo pieces.