Sacha wrote in
:

Thanks, Liz. Many Rosemaries will take quite low winter temps if
they're well-drained, especially. This particular one R. 'Severn
Seas' is fairly tender but it also grows in a most particular and
fascinating way. It doesn't attach itself to a wall as it grows
*down* it but it looks as if it does! It flattens itself tight
against it and, at our friends' house in Salcombe, comes down a wall,
positively cements itself to a path and goes down another wall. Not
so much prostrate as grovelling, really. ;-)

Have you tried 'Blue Rain'?

It has a pretty good prostrate habit, and it is hardier than 'Severn Seas',
though it's a bit of a tiddler - I have a couple in pots, and they have
just wrapped their branches down and around the pots, and not much further
in the 3 years I've had them.

Good long flowering season too.

Victoria