Could it be Lysimachia ciliata 'Firecracker'?

Agree with Beattie

Tell her that it spreads like fury - she'll have her garden over-run with it if she doesn't dig some out each spring! Just chop through the roots and dig a clump out...it's not hard like some plants.

Several pics of these have been posted in the last few days Macpat including mine. This one has lovely deep colours - spreads quite quickly.

Thanks Beattie, Bamboo, Spritz and DRC for your answers.I have advised my neighbour that it will spread. She also has the yellow version which I call Loosestrife and is struggling to keep that at bay.

We had a garden 20 - 25 years ago that was overrun with the green leaved form when we moved in - it's very tough and good under a dry hedge, but we just had too much of it. I dug out big chunks to introduce more variety - it's a good plant in the right place and not too much of a problem.

The yellow "form" I'm guessing is another species called Lysimachia punctata (Yellow Loostrife) which is a different species to L. ciliata though spreads in the same way.

Thank you Fractal, sloppy writing on my part! Sorry, you're right.

No need to apologise Beattie. Just wanted to make the distinction. :-)

Is it true that L. punctata 'Alexander' is less thuggish?

I think it is a little, but only because of its variegated foliage (less vigorous).

I won't bother, then. Thanks, Fractal. I just thought it would make a change....:-(((