Thin, tall but bushy

I really need some help in choosing some plants. My garden has a detached garage in it and a parking space where a car can be parked. Im currently having this all slabbed as it joins into the main patio area. I have soil to plant some plants in but at only a depth of 15cm along the back.

I want to plant some plants there that could climb up and give some privacy but i dont know what to use. There is already a 6 foot fence there but i want to go to about 8 feet. But i cant have something bushy round the base but would like to to be bushy about 5 ft taller or above.

Any ideas of any plants/trees/climbers that would do well here. Roots need to be non invasive too. and evergreen would be great as well.

I know, im asking for something that doesnt exist, but any ideas as i have to look at that space from my kitchen window and really want to include it into the garden somehow. I plan to have large removable pots on the drive area so if you want to use the garage you can easily remove them, but we get to use the space and make it look as one.

 

If you were to extend your fences to 8 foot with trellis or chicken wire there are plenty of climbers you could train up it. They'd take up very little ground space. Maybe some ornamental ivies - Hedera Goldheart is a lovely variegated one, or H Helix Sagittifolia with slender pointed leaves. Ivies are great for wildlife too - the bees love them.
Trachelospermum Jasminoides (Star Jasmine) is beautiful if the area gets a fair amount of sun.

 

Thanks for that, what i was looking at was pleached trees but not sure how big these will grow. I would ideally like evergreen so the ivy may be a good choice. But will the ivy damage the fence if it starts growing through it?
Anyone know the best way to attach the trellis to the top of the fence? the fence i have is the feathered edge type and there are 3 fence posts.

 

I really think you'd be hard pushed to plant pleached trees in 15cm of soil - and they'd certainly have a significant root run. They would grow as big as you let them - especially if you chose Beech or Hornbeam.
The 2 ivies I mentioned are fairly well behaved but planting up a fence is always a bit of a risk...
To fix the trellis I would extend the 3 posts to the height you want and screw or nail the trellis to those.