Part shade, prolific flowers, clay soil, temperate climate...

The Sweeper

...as the title suggests, I need a plant suggestion.

I have a long easement border along my rear fence. This is a temperate climate, and my soil is clay but I'm willing to raise the bed or dig through a lot of organic material to improve the soil. However the fence line actually gets quite a lot of shade as it's sheltered from the sun for most of the day (I'm southern hemisphere and the bed is on the southern lee of a fence at the northern end of the garden).

I can plant over the easement, that's not a drama.

I want to plant something that won't much exceed the height of the fence (2m / 6ft) but that flowers prolifically. I also want to plant clivias at the front of the bed. There's a classic combination of wisteria over clivia that's extremely beautiful when flowering, but I think a wisteria will be too heavy for my fences - and it may take over the neighbour's garden, and I don't want to have to be trimming it back all the time. The shadiness of the bed is what attracts me to clivia in the first place and I'm going for the orange colours (being frankly unable and unwilling to afford the yellow cultivars...)

If anyone knows a wisteria variety that won't go much over six feet I could chat to the rear neighbour about it before planting, but any other suggestions would be very welcome. My local garden centre will source anything I want, but the plant varieties they offer are quite limited and they rarely get anything new in.

Sonnenblumen

Lavatera 'Mrs Barnsley' but other variants available, Acuba, Viburnum Tinus 'Eve Price', Pittosporum Tom Thumb, and Prunus 'Otto Luyken'.

The Sweeper

Thanks - esp for the Lavatera tip, those are precisely what I'm after.