hi and welcome bob i dont think you need to worry about it.it has been a funny year for everything this year i have one in blossom outside for the past month.my leaves on my mock orange have fallen off i got one bud on it for three days.it will stop in time.and go to sleep.good luck.

"could you tell me the reason why i have a 4ft apple tree in my unheated greenhouse ?"

Because you put it there! ;^)

Its the warm weather Bobbee and it will be a few degrees higher in the Ghouse, Your Tree thinks its spring :) Im wondering why its in your Ghouse, It will be fine outside, Apple Trees are hardy in this country :)

Oh! Anchorman, how I laughed and laughed at your reply prior to giving some constructive advice. But you know what? I Just can see where you're coming from. Haha

Bobbee, nature will take it's own course. If your apple tree decides that it wants to flower who are we to argue? Why worry and try to alter things. As Kennyboy suggested, it's been very strange weather this year and plants, unlike us humans who just look at a calendar to find out what season it is, they don't have this luxury and have to try and work things out by what the weather's doing and they sometimes get confused.

As the song goes... Don't worry, be happy...

If I were you, I'd be more concerned about how much bigger it was going to get,but perhaps thats just me being silly.