Hi Marg. Yes, you can graft to the old tree, and not just from a Mac but from thousands of apple varieties. That might not always be the best way to get good bearing trees, but it certainly is done. Google "Top-working apple trees" for loads of information.

Virtually all fruit trees that are sold today are grafted trees. The grower starts with a rootstock chosen for its particular qualities (size, drought-disease resistance, anchorage, those kinds of things) and slips a dormant bud from a particular variety in through a slit in the bark. Everything that grows from that bud is the new variety, and everything else is pruned away. Voila, new tree. Trees grown from seed will not be true to type, as a rule, although they will still be apples, and may be very good or bad.

I wouldn't hesitate to move the seedlings- I doubt you're going to hurt a mature tree much by poking around its roots a bit, as long as you don't use a back-hoe.

If you want to learn about grafting noddle around a bit on this site and via google, and you'll get a glimpse of what's possible. (Keep in mind that not everything possible is a good idea!) Then you'll have a whole new set of questions.

Good luck,

M

Here is a link that might be useful: A grafting forum with lots of stuff

I am looking for IDA Red apple trees or grafts, where would be the best place to get them? Also Damson plum trees?
Thanks,
Martha