What to do with a 'useless' corner?

Dwrgi

Hi everyone, i have a bit of a conundrum.
I have a currently useless corner that is mostly in the shade, but also not very large (probably about 70cm).
Ive tried putting pots there but they don't last. Also slugs have a feast, tried picking off yellowing leaves and going on slug/ snail hunts, but doesn't work. I don't use pellets because of the dog.
Its on concrete so whatever goes there needs to be in a planter. 

Its next to a hedge, so any sun that goes there is minimal, but it is sheltered from the wind.

Its by the patio doors so very noticeable.
Any ideas?

Fairygirl

Heucheras. Hardy geraniums. Some carexes will be fine.
Spring bulbs - many daffs are quite happy with some shade. 
If you get a big enough planter [at least 60cm/2 feet] some of the Japanese azaleas will be fine. Skimmias will also be fine for a while, but would eventually need planted out. Ditto Pieris. 
A home made planter is probably better, and will give you more scope. You can line it and make it more of a bog planter too. Primulas etc would be happy in that, along with ferns, and you could add various other suitable damp shade loving plants of that type. 

Gearóid

I'd have pots of tuberous begonias for summer, cyclamen hederifolium for autumn and cyclamen coum for winter. 

Dwrgi

So much choice! I never thought there would be so much.
Ive never built a planter before, but im willing to give it a go. Im on a budget so can't really justify a custom one.
How deep do they have to be? Is there a minimum? 

 I definitely have to have daffodils, im Welsh so it's a given, i just never thought to grow them there.

Im not keen on growing anything big there as it would likely make the kitchen darker (its the only natural light source, dont ask why, the previous owners did it). 

I'll have to look up all the other plant names though 😂. The only ones i recognised was daffodils, geraniums, begonias and pieris (my nain had one). So im learning a lot here. 
Thanks

Loxley

It's easy to build a low brick wall on a concrete base. You could even get away without mortar. Hardy geraniums, Luzula nivea, Aster divaricata, ferns - and woodland spring bulbs such as cyclamen mentioned above.

Fairygirl

All you need is some decent fencing timber, a post, or heavier piece of timber, that you can cut into four sections for the corners, a saw, screws and a screwdriver - preferably a leccy one. To make it look decorative rather than functional, add a lip round the top. As it would be free standing, it would need a base with holes in it. Then line it with plastic - old compost bags will do, and that protects the timber. Paint it with whatever you like. 
All mine have been done like that. 

In terms of depth, the deeper the better. You don't have to completely fill it with soil, just around a foot will support most plants.

Nanny Beach

One gravel board,or scaffold board,Cheap and cheerful will make a nice planter