Tree/bush suggestions

[Greenscissors]

We have a small (3m) triangular flower bed which is mostly shaded by a brick wall. It is on the upper part of our garden (mostly concrete) which is retained by a 2ft-high brick wall.

The bed is just a bit boring and I'd like some height in it - we have a couple of grasses which look nice in the summer but then disappear.

Any suggestions for a tall-but-not-wide shrub or tree which might work? I was thinking of a Rowan or similar, but have little idea about roots - we don't want to compromise the retaining wall (whatever we plant would be less than metre away) or have something which will grow very large very quickly.

Acer Sango Kaku is a fabulous plant. Easy to,look after, has shallow roots and is a joy all year round. It leaves emerge copper yellow in the spring, change with every season and when they fall they have scarlet red stems all winter through. I got my mine online from Crocus plants

Am Amelanchier is a beautiful shrub/tree and would fit the bill. In the spring it has lovely blossom and new bronze leaves, the leaves then turn green and the berries develop. In the Autumn it has red berries and russet leaves.

Thanks, I'll check both of those out.

Amelanchier are beautiful but need lots of water, it is likely to be very dry near a brick wall.

Berberis is one of my favourite shrubs. Copes well with dry shade, evergreen for winter interest, orange flowers right now and beautiful berries in autumn. Nothing in summer but it makes a nice backdrop. Can prune to different shapes- bush, tree etc

Downside is that it’s spiky as anything, but that wouldn’t matter too much at the back of a bed.

Acer Sango Kaku doesn't like to be in a draught. Something to think about if you're putting it in the higher part of your garden.

This is all a lot more complicated than I would like! The suggestions so far are all lovely but not suitable for one reason or another with a bit more reading. Thank you, though!