The top ones look like Love in the Mist (Nigella) - there would have been pretty light blue flowers before the seed heads formed? But as they seed themselves around so much, some people pull them up!

Sorry, not sure about the third pic.

agree the first are nigella seed pods.
the second could be golden rod/ penstemon [unlikely] phlox, aster. there are several that start like this and waiting for the flowers is the best option really.

Thank you for the reples, so it seems that perhaps neither are weeds. I think the 3rd pic could be Phlox, the name sound similar and I'm sure this came up in neat lines suggesting it was planted, last spring though if I recall correctly.

"Horses for courses" I wouldn't class either as a weed unless they were in the wrong place - but then a rose is a weed in an asparagus bed!

My first impressions of #3 was Phlox

The love-in-a mist have those attractive seedpods which some people pick for flower arranging but as they are an annual, I leave mine to ensure new plants with lovely blue flowers next year. (Ithink you can get white and pink as well now.)