On 2013-05-18 12:49:35 +0100, Chris Hogg said:

On Sat, 18 May 2013 12:24:05 +0100, Timothy Murphy
wrote:

I have an old stone (granite) wall around my cottage,
and would like to grow some small flowers on it.

I've seen recommended
Trailing bellflower (campanula poscharskyana) and
Adria (or adriatic or dalmatian) bellflower (campanula portenschlagiana).

I don't think my local garden centre sells either of these.
Can anyone recommend an online site for them?
Either plants or seeds.

Also, any other recommendations?

Erigeron karvinskianus
http://apps.rhs.org.uk/plantselector/plant?plantid=729
Grows it the tops of numerous stone walls in the West Country, under
the most difficult of conditions. Seeds itself freely. Fully hardy, I
believe. See here for the Google search page
http://tinyurl.com/cckq3d9

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.
--

Sacha
www.hillhousenursery.com
South Devon
www.helpforheroes.org.uk