harry wrote in news:c626d701-99a9-4f81-a0aa-
:

I don't think any of these suggestions will grow in an exposed coastal
area with shallow soil.

I've just stubled across this interesting/attractive option:

Vitex agnus-castus: http://tinyurl.com/6vxgco9

However, they attract bees, which could be a pain when you are sitting
under it, in close proximity!

Al