Unidentified blue flowers

[bungles]

I hope one of the experts on this forum can help me identify these beautiful flowers that cover a wall in our garden in London and begin flowering May-June. I'm assuming they are wild as they seem to be able to sprout from the tiniest crack and can get out of control very quickly. The flowers are 2-3 cm across. I hope that someone can help me identify them as I've spent hours looking at photos online and not convinced I have identified them.

[Jonners]

They look like some kind of Campanula. Quite possibly self seeded from someone's garden. But still beautiful flowers as they cascade down the wall.

[bungles]

Thanks Jonners. That's encouraging as I had campanula as one of the contenders but couldn't find an image that matched closely enough to be sure. The leaves are quite distinctive too.

The options I had under consideration were dog violet, wild blue phlox and speedwell. You can see that I'm no expert on identification but I do enjoy taking photos. Thanks again!

[davidbr]

It's Trailing Bellflower (Campanula poscharskyana), an increasing garden escape on town walls in the south. It makes a fine sight in and around the centre of Bristol

C. poscharskyana is one of two superficially similar species; the other is Adria Bellflower, Campanula portenschlagiana;


Adria Bellflower, Campanula portenschlagiana

[bungles]

Wow! You guys are good!
Many thanks David - much appreciated.

The plant is incredibly invasive on my planting wall and I have to weed back quite heavily to allow the other plants to thrive. It even seems to be happy to grow out of the mortar between the bricks.