"DH" wrote in message
...
So then, would it be possible to graft a branch of a desirable citrus
to
these trees? Just wondering, since I have one of those "fruit
cocktail"
trees growing out front, and have harvested oranges and lemons off of
it.
(No grapefruit yet, but it is only about three years old.)

It's usually done with a bud graft. Wait to graft the bud until the sap
runs, i.e., the bark "slips". Might be a several months before you see
a new shoot and several years before you see any new fruit. The way we
usually do it is grow a sour orange from seed until the main leader is a
few feet long, then bud-graft the bud from the desired tree. When the
bud shoot is 18-24 inches long, cut off the sour orange leader. -Olin