In my zone if we can graft on chokecherry or anything that help on hardiness of the climate we will make a considarable step in the progress and this succes we badly need it because what is on the market is about all not made for in our place,fact is that the destruction of our trees by winter season breake the courage of many and teach to our children to keep away from it.This year was the worst winter season in 35 years and find something for our place is greatly necessary.I have made reaserch for what i say and the results of it are speaking.I bless every try or efforts that are made for even a drop to success in giving possibility to fruit trees to stay here alive adding lot of hapiness to many homes....

No, actually it's a good question, blaze. I have a 4-in-1 peach I bought on a lark. Not a big fan of multi-grafted trees, but I wanted to experiment with this one. What you can frequently see happen is that the stronger variety can "overtake" some of the less vigorous varieties. The recommendation is to figure out which is a less vigorous variety, or which graft seems to be lagging a bit, and plant that graft facing south. Place the most vigorous graft if possible facing north. And, keep the more vigorous variety pruned down so it doesn't overtake the the other varieties. The varieties will bloom when they bloom, and will produce just the same as if they were an individual tree. So yes, in that way they do function independently. And, make sure you hang good, permanent tags on your various grafts, close to the trunk. Make sure you loosen the tags and the branches grow in diameter. That way, you're not try to guess what branch is what variety down the road. Patty S.

I have a feeling if you chopped out 90% of the trees you would just provoke them to send out a ton of new suckers. What I would do is trade for scion wood http://www.nutgrowing.org/scion.htm or buy some from a place like this http://www.masonvilleorchard.com/scionwood.htm then I would top work all 9 trunks using a grafting method like this http://www.youtube.com/watch?v=XpgbpbewU3E then you would have fruit in just a couple of years from the new grafts and could still keep the original fruit tree and the roots of the others. With vigorous rootstock they always come back when you cut them down to one stock. If any of the grafts did not take I would then cut that stock out. Do you know what plum they are? The root stock sound like American plums http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CDgQFjAF&url=http%3A%2F%2Fwww.ag.ndsu.edu%2Ftrees%2Fhandbook%2Fth-3-39.pdf&ei=kbg7VMPvJqf28QH3yYHYCA&usg=AFQjCNG_4yacSh8idfYdggUukUGd_1tMcg

See through yellow plum sounds like Shiro. Shiro is a early ripening Japanese type hybrid. Shiro is very juicy and can get large with fruit thinning. I think you are exaggerating when you say the stone is 2-4 inches. Shiro is somewhat self fertile. If the plums are small and have an apricot flavor it may be La Crescent, and American hybrid plum with Shiro parentage. European type plums are self fruitful but yellow European plums are rare so I doubt it is European.