What to plant in new 'toughs' on decking

My husband has just laid decking at the back of our north facing garden, the sun at this time of year is starting to finish right here before setting.

He has created a seating area and behind it trough like containers for plants.

I would prefer to put some evergreens in for year round interest as you look from my kitchen and patio doors up the garden straight at it and it can cover some of the decking (why are men obsessed with decking...)

Anyway, can anyone suggest what to plant in it?

I would also like colour to popup throughout the year if possible.

Thanks in advance ;-)

 

Hmm..

That's a "tough" decision.

(sorry!)

 

what about some penstemon, they have lovely flowers (allsorts of colours) from about now right up to late autumn (some of my older ones have maintained their flowers well into winter!) and the leaves are evergreen. They need cutting right down in spring once the last frosts have past but other than that are fairly low maintenance and really easy to propagate.

 

Sorry too easy to mispell on the iPhone - I meant to say troughs!

The penstemon look lovely fromteh pictures, are there any other flowers/shrubs you would suggest that go with these in planting?