Fruit trees.. Well, it is tricky for me. The pears has something ( if I recall right I think someone mention some amid compounds) in nectar cause of which bees avoid them, but wild pear ( Pyrus pyraster) has no this and bees are all over them. This I saw practically, cause one huge tree of pear whole in white of flowers and no single bee, but some 200 meters wild pear sounds like the swarms are on it. Next thing cherry and wild cherry - Prunus avium. Bees like more the wild cherries. The hives were beneath one huge domestic cherry and I was surprised to not see any bee on their flowers, but 50 meters from the hives again "swarms" on the wild cherry. For me wild cherry here is very important first of all of great amount of nectar and pollen which gives great boost to colony build up, and at the end if the weather behave some aromatic honey for me before main flow here.
Plums are something which also gives nectar and pollen. For much I saw, all are well attended by the bees.
But to plant all these fruits is a gamble here cause we have unpredictable spring and sometimes flowering passed in rains, frosts, winds..
But again when the year is right, it gives you great smile on your face. Like this spring was never such great for a wild cherry here and other forest fruits. I think the most time of their flowering was nice weather. So I got huge amount of nicely drawn combs, some honey yield, bees built their colonies superbly ( even later main forage failed and all the strength not used at full..).
Beside these fruits here also is important early - cornel. Again, it flowers also when is snow on the ground, but when come period of warmer weather in late winter-early spring bees are first on it's flowers ( also gives nectar and pollen) and let say here the first sources of nectar and pollen in new year in important quantities. And nice and refreshing drink You can get from it, some make jams or so.
Almost forgot lately we had some shrubs of Black chokeberry which turned to be very interesting to the bees ( I don't know how much of nectar it gives to the bees, but pollen for sure), and also we got its fruits for us..
Blackberry and raspberry - in our conditions they give great amount of nectar ( but no trees..).
Interesting thing for the Ivy - in your conditions as you say it is OK, here is the most undesirable as winter store for the bees. I think something like honeydew, lot of indigestible matter for the bees and in winter bees got -you know..
