Trees or shrubs?

Bagpuss57

I am trying to find a tree or shrub that can be used for privacy, tall enough to screen overlooked windows. I imagine it needs to be about 10ft to do the job but have seen that most trees take up to 10years to get to the height I need. I thought maybe a shrub might grow a little faster? I was thinking maybe a red robin photinia, an amelanchier or a cornus but it needs to be happy in my clay soil. Does anyone have any good advice or ideas please? I'd love something with some seasonal interest or something that flowers if it is evergreen.

Pete.8

I'd go for an amelanchier.
They grow quite fast (mine is about 10ft my neighbours are about 12ft) and they look beautiful throughout the year (but bare in winter).
Leaves flowers and berries all look great  - a lovely shrub and the birds love the berries

Bagpuss57

Thanks Pete8 I am hoping to go looking soon to see who sells them. Bonus that the birds like them too. 

Papi Jo

I support @Pete8 's suggestion for an amelanchier. If you need something that really gets tall quickly, then I'd go for Amelanchier alnifolia ‘Obelisk’ which I've got in my garden. Planted in 2014 it now reaches 3 metres high.