I like most of the suggestions but the wall doesn't look tall enough to train a Japanese quince - they are rather untidy straggling bushes and do need a certain amount of pruning at the right time in order to produce flowers and fruit so not low maintenance. I'm not in favour of Cotoneaster horizontalis either which I believe has just been added to the list of "undesirable" plants. I found it seeds itself around (or the birds do it for you) too much for my liking (into our tarmac drive for instance and on top of our wall) and has proved impossible to kill. An alternative might be the unusual very pretty slow growing evergreen is Osmanthus heterophyllus 'aureomarginatus' with green/cream/pink leaves, rather like a holly, which can be pruned to shape.
Cotoneasters are now getting a bad name, but I must admit, anything that self-seeds or seem 'easy' is now labelled weedy or thuggish. In fact, it was the free-ness of this shrub that made me think it would suit that wall.
Another alternative could be box balls planted at even intervals and have Cyclamens and Crocuses, Violas fill the base. Other than Buxus Sempervirens, Ilex Crenata can be an alternative.
I'm a big fan of heucheuras and ferns in shady areas. Heucheuras have a huge range of coloured foliage and last throughout the year with the added benefit of tall spikes of little flowers (hence their other name of Coral Bells,which bees love).Heucheuras are different some prefer deep shade and others can cope with a lot of sun. Ferns mostly die back but the Hartstongue shown lasts all year. Watching new fern fronds unroll is a wonderful. Just check which fern as some need damp shade and others love dry shade. The photo is of some heucheuras and ferns in pots down my shaded sideway .
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Another alternative could be box balls planted at even intervals and have Cyclamens and Crocuses, Violas fill the base. Other than Buxus Sempervirens, Ilex Crenata can be an alternative.
Just check which fern as some need damp shade and others love dry shade. The photo is of some heucheuras and ferns in pots down my shaded sideway .