ideas for a planting plan

You can use pots of lilies or dahlias to fill the gaps. If your border is in its first year you need to allow space for the perennials you have planted to spread next year.

You might not have a gap at all next year if the geranium has room to spread.

Yes pots would be a good way to go, I think really the problem is that the geranium has spread too much and been a bit of a thug when I think about it so perhaps the thing to do is take some of it out. It is so difficult though I always have a colour scheme in mind (blues purples and reds) and then try to fill the bed with colour for at least summer and autumn and every year find myself dissatisfied with the result

Is it 'Johnsons Blue' by any chance? That's a real thug.

If I'm sticking to a colour theme I use pots of box or any dark green shrub that can be pruned then you don't have an unwanted colour clash.

No it is geranium psor - something -it is about 4ft high and cerise and flowers early summer a lovely thing but now I have cut it back and I have this huge gap.

I do think geraniums are useful though.

Whilst I am on the subject - I bought and have been moly-coddling an anemone "wild swan" I have 3 which are still in pots as I am unsure where they should go I live in the South and they were bred in Scotland so am wondering if the sun would be too much for them