When i looked at the trees it said you had to buy the two apple trees M&F.
Is there any trees (apple) where you dont need to buy both sex trees?
Many thanks
It's not male/female - they all produce pollen and stigmas (stigmata?), or half your apple trees wouldn't set fruit! The thing is that most varieties aren't self-fertile. They need to be fertilised by a genetically distinct individual, not another clone of the same variety or a flower somewhere else on the same tree. Some pears are very fussy, and won't be pollinated by close relatives - sometimes the parents of the hybrid you're growing won't do the job, either. I guess it's like incest taboos, a thing to help maintain genetic diversity.
There are a few varieties of stone fruit that are self fertile, and I think a few apples will set a poor crop without pollinators nearby. However, you do normally need another tree, although often a neighbour's, or crab-apples in a hedge, will do OK,if you're in that sort of suburb! (To add to the fun, some varieties don't produce viable pollen, so although they set fruit normally, they won't pollinate your other trees; you need three - a pair to fertilise each other, plus the one that's firing blanks.) You can buy multi-grafted trees from specialists - up to five or six varieties that will cross pollinate growing off the same trunk.
Furthermore, you need varieties that blossom at the same time. Most catalogues give you a number that indicates early, mid or late flowering (some use a 5 point scale), but not all garden centres or non-specialist retailers give all that information.