No idea on #1
#2 is Sedum spathulifolium the Spoon-leaved stonecrop
#3 is not a weed in my view, but I can't remember its name!

No. 1 is Valerian, forgotten its proper botanical name, and No. 3 is Cornflower - Centaurea cyanus, which is only a weed if you don't want it growing where it is growing. People go out and buy this plant...

Thank you both so much! I'm going to go and read up on these three new (to me) plants :)

I must have lost more brain cells - takes longer for names to surface, but it finally has - Red Valerian is Centranthus ruber...

Brilliant, thank you :) I'm writing it all down in my little notebook so I can make little stake things to put near the plants until I can remember their names.

I Googled the 3rd one and I think it's maybe centaurea montana, the leaves look similar. It's so wonderful to know the names of things and seeing all the images!

Hi, welcome to GoY, I agree with Bamboo, that it is Centaurea cyanus, the leaves are wrong for montana. also agree with the other 2 id's, Derek.

Are they? I thought the cyanus looked too stringy and skinny compared to mine, overall. There's no spaces between any of my plant, it's just a solid mass of leaves. I looked on rhs and the Montana one looked the most similar, taking into account the colour and everything else.

I'll bow to everyone's superior knowledge on this one though :)

Thanks for the welcome :)

Given that C. cyanus is an annual, it's actually more likely yours is C. montana, Fifegarden, now that I think about it - yours looks like its been there a while, but the annuals do seed themselves. Whatever, tis a cornflower either way;-)

It's at least a couple of years it's been there, Bamboo. It went away in the colder months but what's in the photo is new growth from this year and it's a bigger spread from last years patch.
I've been looking at lots of photos and it's closest to Montana, I think. It's a very pretty cornflower, whichever it is.