I am planting a mixed native species hedge within my apiary at the moment, I have about 100m to do so I am part way through planting the best part of 500 bare root trees.
I would recommed borrowing a copy of "Where have all the flowers gone" by Charles Flower (it is pretty expensive and mainly about wildflower meadows). It has a chapter specifically detailing installing native species hedges to provide forrage and flowers.
The hedge I am installing is 50% Hawthorn, planted as a double row 5 trees per m approx 1m between rows. Plant 1 row as hawthorn (1 tree every 40cm) this provides the thorny structure of the hedge which will make it stock proof in a couple of seasons, it is also great for nesting birds and early season flowers. The second row should be a mix of native species. There is a % mix recommended in the book. However, as there were some other trees we wanted to include we varied our mix slightly to:
Hazel 15.0%
Blackthorn 4.0%
Field Maple 5.0%
Wayfaring Tree 2.6%
Holly 2.0%
Hawthorn 50.0%
Buckthorn 5.0%
Dogwood 7.0%
Spindle 2.6%
Dog Rose 2.6%
Crab Apple 2.0%
Elder 2.2%
We bought ours from Mill Farm Trees as they were the best value, for bare root trees which need to planted around now.
I would steer clear of a solid Blackthorn hedge as it spreads by suckering and will gradually advance across your apiary. Dispersed individual blackthorns give shape to your hedge creating sheltered areas.
I would also dip all bare root trees in a microrhizoal fungi solition before planting as this will establish a better root system.
I tried to buy a tree planting spade but they cost a fortune so ended up buying a drain spade from Toolstation. They are basically the same and it cost about £20 and was invaluable for planting bare root trees. Just open a slit tuck in the tree roots, drop in a cane, heel in and put a spiral tree guard over the top.
Hope this helps.
Ross