Anybody tried putting a tastier Prunus on emarginata rootstock? they get pretty large but i see no problems with a 30ft plum/cherry tree

I haven't, but I have grafted Montmorency to a small bush cherry from China. It took ,but then I forgot about it and let it outgrow the graft. I'll get back around to it one of these days.

Your experiment sounds interesting. I bet it would be more successful to graft it to a small one rather than a big one.
John S
PDX OR

I grafted some weeping cherry onto three bitter cherry tree seedlings in my yard. Two of them are grafted at 12' height, did these in 2010, the third is grafted at about 4' high, grafted in 2009. They are all doing well. The taller ones are near the street and I wanted a unique looking specimen tree that wouldn't be dropping fruit on the sidewalk.

I also experimented with grafting Emperor Francis, White Gold, Kordia, and Hartland cherries onto some smaller seedlings on Jan 31, 2010. Four of the five trees I grafted are doing OK. I used whip and tongue grafts, wrapping with parafilm.

My next experiment will be to climb up in the tall bitter cherry tree and graft in some pink flowering ornamental cherry. Would be neat to see pink splashes of blossoms in the sea of white blossoms in the spring.