Questions

I have a garden space of roughly 50 feet by 40 feet which I would love to fill up with trees (not fruit-producing), as a sort of mini-forest (I don't want to be cutting grass). This space is about 20 feet from the house, but is beside a concreted area.The features I would like are: native Irish if possible, quick-growing, good cover (from the neighbours), a nice blaze of colour. I'm probably asking for too much, but can you suggest anything?

Newly bought tree is to tall for my site can I shorten by cutting off the top on a slant above a bud.

I have 2 climbing hydrangea on a south facing wall for a no. of years. Each year it is covered with loads of buds but the buds never mature into decent flower heads.

Please could you recommend plants for my south facing (no shade) and exposed to the wind garden. Very clay slow - slight slope.

would you happen to know the name of this tree?

Could you please advise me what to do with a 20ft concrete retaining wall at the back of my garden, the top of which is the end of my neighbours garden, which is fenced, so I have no access to plant creepers. To add to my problems my garden is completely concreted (by previous owners), so no soil to grow anything!! It is driving me mad as everything is very grey and depressing. Please help.