I've just planted a plum tree on my allotment,when someone has said that I should cut the top off,otherwise they said it could grow into a popular. What does this mean,and when is the best place and time to prune a plum tree.Many Thanks.
Do you think they meant a poplar? A poplar is a very tall tree. Did you not get planting and care instructions with it when you bought it?
How old is the tree? Did you buy it from new? That would determine what do you do with it pruning wise.
See if you can find some pruning instructions.
I know that it is always recommended that the 'vertical shoots' should be taken out of fruit trees, to make them fruit on the lateral spurs ( short side shoots).
This is also much easier for you when picking fruit.
Topping out of fruit trees I think is standard practice. Have you ever been in Devon and seen the cider farms? Their trees have only 4-5 main branches and all are trained sideways.
Don't prune in winter, as this carries too much risk of introducing a fungus disease called silverleaf. Cut back the verticals by about half of the new growth on a young tree, or more if it wasn't done last year and it's getting excessive. I've pruned one of mine already, and I'll probably put off the other till next spring; it's buried in rampant raspberries, which I plan to deal with over the winter.