Can a cherry tree become a green gage if you don't prune it?

No. You either bought a greengage/plum in the first place, or you're eating some kind of cherry from the tree. Did you keep the label so you know what the Latin name was? Photo? Sometimes plants are mislabelled when you buy them.

The Cherry part has died on your tree, the root stock has taken over. Now you have a yellow plum or greengage. Eat them or make jam before the birds get them.

But it won't have been because you didn't prune it!

The rootstock on which your cherry was budded or grafted may have been a prunus ceragifera or myrobalan cherry plum. By not prunung, buds have developed below the bud or graft, taking all the energy in to it's growth.

Well, its a point of view, but I suspect there's another reason why this has happened to do with watering.

Sorry Bamboo I agree with Dr Bob the rootstock has taken over as Plantkiller didn't keep shoots from below the graft cut back.

Okay, I'll come clean - I think, as it was in a pot for longer than it should have been, it was not watered sufficiently - the graft on the top died back, and the rootstock, naturally enough, took over. Not pruning out growth off the rootstock would cause this trouble, if it were growing, but not just from keeping the cherry variety unpruned.

Thanks to all who helped, knowledgable neighbour sure it is gree gage or some type of plum. Family safe!

And lucky you - I love greengages straight off the tree, used to have one.

So a cherry can be grafted on to a plum?

Yup they are both in the same 'family'

Yes I agree with Moongrower, but it is interesting that you cannot graft or bud an apple on a pear although THEY are from the same family.

Indeed Dr B... I wish I understood more of the why's an wherefore's!

Yes Moongrower, rural science is a fascinating subject. I gave my notes to a student some 40 years ago on apples and pears. If you can browse on chromosones, apples and pears are not compatible. Searching through my brain 48 comes up for one of them.

Right... I'll take your word for it Dr B

Thanks :-) Strange isn't it.

Suckers from a vigorous rootstock could potentially take over a tree. Dwarfing rootstocks are less of a threat. The best way to remove a sucker is to slice it off at the root - remove the earth above the root to make it easier. You can cover the root scar with a sealing product.

P.S There is no great mystery with the Apples and Pears - they are indeed in the same family, but they are not in the same genus (unlike cherries and green gages, which are both species of Prunus).

Species are made distinct by their inability to reproduce with other species, though there is occasional hybridisation.

The different numbers of chromosomes in Pyrus and Malus shows that they won't be compatible, so the person who gave them their scientific names (long before the genome project!) got it right.