"Marley1372" wrote in message
...
sour cherries are self fertile and do not need pollinizers. They also do
not
pollinize sweet cherries

I'm thinking of
top-grafting his S.N. onto my Napoleon but I'm not sure if it's possible.

"top" grafting refers to grafting at the top of a standard, as opposed to
"bottom" or bud grafting, which is grafted at the base of the plant. This
wouldnt be possible because your plant has already been grafted.

My RHS encyclopedia of gardening does suggest that grafting twice is not
only possible but in fact necessary for some species. Is this not possible
at all for sweet cherries?

You could try
to graft buds from the other tree on you yours, but it would be way easier
to
spend 30 bucks and get a second tree.

I don't need to spend 30 bucks, only about 600 yen (about 5 bucks) for
another cherry tree. Actually I was worried about the eventual size of the
tree more than the cost because I'd heard that the trees can grow very big.
Anyway today I was chatting to some people who have two twenty-five year old
cherry trees in their garden, and they said that their trees are only about
two metres high. Perhaps the common Japanese cherry trees are on dwarfing
rootstocks? The places I go to don't have much information about the trees
they sell. I bought two apple trees a few years ago not realising they were
on dwarfing rootstocks.