Posted: 03/02/2016 at 19:01
I'm happy to be wrong but depending on the variety you need two pear tree's for them to cross polinate and they need to be in the same polinating group or the one either side - if that makes sense.
You may get away with one tree, if someone else on the allotments has a pear tree but the polinating rule still applies. Distance between the tree's needs to be considered too, that's if you choose to get one on the basis another plot holder has one which can be cross polinated with yours. Bee's are known to travel long distances but they are not necessarily going to fly between your tree and another plot holders tree if the distance is huge or if there aren't many bee's about.
My plan is to get two tree's, pears don't seem to be that popular here, only one tree on another plot.
I had a similar problem as you last yr with apple tree's, nowhere for them to be planted and was advised to clear the weeds and dig over an area about 3ft square, then plant them out. You can then dig over the ground around them at a later date providing you ensure the tree bed remains weed free.