In article , Alex Woodward
writes
I have an heather bed (semi-successful) and would like to know other plants
that will compliment it. The soil is probably alkaline

That might be why it's only semi successful - many heathers will not
tolerate an alkaline soil.

and is clay based.
Having said that, I have recently added huge amounts of peat based compost
and horticultural grit etc to lower its level and help it to drain. Recently
added spring heathers are doing great, but the summer flowering ones seem to
be struggling.

IIRC that's right - the winter flowering heathers are Erica carnea and
will tolerate lime, the summer ones are other ericas and Calluna and
need a non-alkaline to acid soil.

--
Kay
"Do not insult the crocodile until you have crossed the river"