Gyve Turquoise wrote:

"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?

Most of the double grafting I've heard about is to produce a tree of a certain
size. But bud or scion grafting to the tree would certainly be possible. That
is how they produce trees with more than one variety of fruit on it. My mom and
I have trees we have planted just to graft different things to them. Most of
the trees are apple trees but why not try to graft to your tree and see what
happens. Experimenting can be fun and just maybe, rewarding also.

Marty