I haven't got my cherry tree yet, but assuming grafting a cherry is anything like it is for apples, here are some ideas: Do your pruning and scion collection during dormancy. I'm not sure where you are, but here in the northern hemisphere (I am in Wisconsin), right about now in March is a good time for collecting scion wood. Bag it and put it into the refrigerator until later. Best time for grafting is when the trees just start to leaf out. An experienced friend of mine says the best time is when you see the first dandelion bloom, then you know it's time. My guess is mid-April, but with this odd weather, who knows. You basically want to make sure the sap is running in the tree before you graft on. I'd consider chopping the tops off your trees, and throwing most of the extra wood away, but save some scions from each, make the trade and then graft up top near or on the central leader. Basically trade the tops of the two trees -- I mean, why not?! Then your new scions in the tops of the trees will get maximum sunlight which should help ensure success, assuming they don't dry out. You might want to graft two or three sticks onto each tree just to ensure success, because occasionally they die. Any graft technique should work -- saddle, whip & tongue, cleft, bench -- whatever you prefer, and based on the size of the wood you're grafting together. Best of luck to you.

You'll likely get a better overall result if you follow the advice given and graft the two cultivars directly onto each other instead of trying to perform some sort of exotic graft down below the graft junction or onto a sucker. For your intents and purposes (the way you are asking) yes, you'll get the "same" results. But if you are going to get into the excitement of grafting, why not find a friend or neighbor or somebody who has a 3rd or 4th variety and add those onto your tree? That's when the fun really begins.

I have read that in this instance that people can do two grafts. The native variety being the most hardy and strongest rooting, then a short intermediary piece which can bridge between the native and fruiting varieties. Can anyone assist? Or know someone who can? I have cut down a large native cherry and would like to graft lapins and stella to the sprouts which are sure to come up this spring. "example taken from plum/almond stone fruit grafting" - " Also (and this is where the fun starts) most fruit trees in the Prunus genus are sometimes compatible with each other: almonds, apricots, nectarines, peaches, and plums all are compatible for grafting, but occasionally it's complicated. For example, some plum rootstock is not compatible with peaches or nectarines; and some almonds require an intermediate step before grafting onto some plum rootstocks."

Jim Cummins once wrote about dubious nurseries grafting peach to sand cherry to get a dwarf. It was kind of a funny write-up. I wish I'd saved it, but here is the gist. 1. Nursery plants 1000 sand cherry rootstocks and grafts peaches. 2. One year later, nursery digs up trees, 100 of them break at the graft union. 900 available for sale. 3. Joe Customer sees peach trees advertised in catalog. "Delicious full-sized peaches from a dwarf tree!" 4. Joe orders two trees. He plants them. 5. Waters and cares for them first summer, but one dies. 6. The following spring Joe is delighted to see his remaining tree flowering. It sets fruit. 7. All summer long sees the fruit developing, gets excited about mouth watering peaches. Anticipates calling the neighbors over to share in his bounty. 8. Before peaches are ripe, remaining tree collapses due to graft incompatibility. 9. Joe figures he must have done something wrong and orders four more dwarf peach trees.