On Sat, 18 May 2013 13:11:12 +0100, Sacha wrote:

On 2013-05-18 12:49:35 +0100, Chris Hogg said:
Also, any other recommendations?

Erigeron karvinskianus

I'd heartily endorse this suggestion. It's a delightful little plant and
flowers over a very long period. Depending on the scale of the wall
(and if it's possible) I'd also suggest lavender which likes the good
drainage of growing in a wall, valerian which insects love too and
Helichrysum Italicum, Phlox subulata and Persicaria bistorta. Some of
these will depend on the sun/shade aspect of the wall.

Yes, Erigeron is great stuff, it was recommended to me here (maybe by
Chris and Sacha too!) for stone walls, it has done really well. All came
back in spite of the very hard winter, I even bought a few more plants
this spring.

Valerian is good but can be invasive, I found.

--
Gardening in Lower Normandy