Gardening Questions Does anyone know what this Plant is ?

It could be the perennial cornflower (centaurea montana) which is pretty free seeding.

That's exactly what mine do - just appear in odd places! I have so many that I am having to treat them like weeds. A few where I want them - lovely. Lots where I don't - a nuisance!

Looks like Verbascum - also known as Mallow. We get them all the time and treat them as weeds. They are quite pretty but attract LOTS of caterpillars.

Thanks guys for the replies, i will keep an eye on them, they are in a empty space , which needs lots of plants so everything helps !!